refactor: полный UUID рефакторинг tasks.py + audit log + WS member_id

- Все slug ссылки заменены на UUID (assignee_id, reviewer_id, watcher_ids, author_id)
- TaskAction записывается при каждом изменении задачи
- _system_message принимает actor: Member вместо actor_slug
- ConnectedClient хранит member_id для task event фильтрации
- broadcast_task_event фильтрует по member_id вместо slug

src/tracker/api/tasks.py

@@ -1,5 +1,6 @@
 """Tasks API — CRUD + take/reject/assign/watch."""
 
+import datetime
 import uuid
 from typing import Optional
 
@@ -10,7 +11,9 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload, joinedload
 
 from tracker.database import get_db
-from tracker.enums import AuthorType, ChatKind, TaskPriority, TaskStatus, TaskType, TaskActionType
+from tracker.enums import (
+    AuthorType, ChatKind, TaskActionType, TaskPriority, TaskStatus, TaskType, WSEventType,
+)
 from tracker.models import Task, Step, Project, Member, Message, Chat, TaskAction
 from tracker.api.auth import get_current_member
 
@@ -19,6 +22,12 @@ router = APIRouter(tags=["tasks"])
 
 # --- Schemas ---
 
+class MemberRef(BaseModel):
+    id: str
+    slug: str
+    name: str
+
+
 class StepOut(BaseModel):
     id: str
     title: str
@@ -31,7 +40,7 @@ class TaskOut(BaseModel):
     project_id: str
     parent_id: str | None = None
     number: int
-    key: str  # e.g. "TE-1"
+    key: str
     title: str
     description: str | None = None
     type: str
@@ -39,9 +48,9 @@ class TaskOut(BaseModel):
     priority: str
     labels: list[str] = []
     assignee_id: str | None = None
-    assignee: dict | None = None  # Member object for display
+    assignee: MemberRef | None = None
     reviewer_id: str | None = None
-    reviewer: dict | None = None  # Member object for display
+    reviewer: MemberRef | None = None
     watcher_ids: list[str] = []
     depends_on: list[str] = []
     position: int
@@ -84,8 +93,13 @@ class AssignRequest(BaseModel):
 
 # --- Helpers ---
 
-async def _get_project_chat_id(db: AsyncSession, project_id) -> str | None:
-    """Find project chat UUID."""
+def _member_ref(m: Member | None) -> dict | None:
+    if not m:
+        return None
+    return {"id": str(m.id), "slug": m.slug, "name": m.name}
+
+
+async def _get_project_chat_id(db: AsyncSession, project_id) -> uuid.UUID | None:
     result = await db.execute(
         select(Chat).where(Chat.project_id == project_id, Chat.kind == ChatKind.PROJECT)
     )
@@ -93,21 +107,36 @@ async def _get_project_chat_id(db: AsyncSession, project_id) -> str | None:
     return chat.id if chat else None
 
 
+async def _record_action(
+    db: AsyncSession,
+    task: Task,
+    actor: Member,
+    action: str,
+    field: str | None = None,
+    old_value: str | None = None,
+    new_value: str | None = None,
+):
+    """Record a task action in the audit log."""
+    db.add(TaskAction(
+        task_id=task.id,
+        actor_id=actor.id,
+        action=action,
+        field=field,
+        old_value=old_value,
+        new_value=new_value,
+    ))
+
+
 async def _system_message(
     db: AsyncSession,
     task: Task,
     chat_text: str,
     task_text: str | None = None,
     project_slug: str = "",
-    actor_id: str | None = None,
+    actor: Member | None = None,
 ):
-    """Create system messages: one in project chat + one in task comments.
-    
-    chat_text: short message for project chat
-    task_text: detailed message for task history (if None, same as chat_text)
-    """
+    """Create system messages: one in project chat + one in task comments."""
     from tracker.ws.manager import manager
-    import datetime
 
     prefix = project_slug[:2].upper() if project_slug else "XX"
     key = f"{prefix}-{task.number}"
@@ -115,24 +144,26 @@ async def _system_message(
     now = datetime.datetime.now(datetime.timezone.utc)
 
     chat_id = await _get_project_chat_id(db, task.project_id)
+    actor_id = actor.id if actor else None
+    actor_slug = actor.slug if actor else "system"
 
-    # 1. Task comment — detailed history
+    # 1. Task comment
     task_msg = Message(
         task_id=task.id,
         author_type=AuthorType.SYSTEM,
-        author_id=uuid.UUID(actor_id) if actor_id else None,
+        author_id=actor_id,
         content=task_text,
         mentions=[],
     )
     db.add(task_msg)
 
-    # 2. Chat message — brief notification
+    # 2. Chat message
     chat_msg = None
     if chat_id:
         chat_msg = Message(
             chat_id=chat_id,
             author_type=AuthorType.SYSTEM,
-            author_id=uuid.UUID(actor_id) if actor_id else None,
+            author_id=actor_id,
             content=chat_text,
             mentions=[],
         )
@@ -141,11 +172,12 @@ async def _system_message(
     await db.flush()
 
     # Broadcast task comment
-    await manager.broadcast_task_event(str(task.project_id), "message.new", {
+    await manager.broadcast_task_event(str(task.project_id), WSEventType.MESSAGE_NEW, {
         "id": str(task_msg.id),
         "task_id": str(task.id),
         "task_key": key,
         "author_type": AuthorType.SYSTEM,
+        "author_id": str(actor_id) if actor_id else None,
         "author_slug": actor_slug,
         "content": task_text,
         "created_at": task_msg.created_at.isoformat() if task_msg.created_at else now.isoformat(),
@@ -153,14 +185,15 @@ async def _system_message(
 
     # Broadcast chat message
     if chat_msg and chat_id:
-        await manager.broadcast_task_event(str(task.project_id), "message.new", {
+        await manager.broadcast_message(str(task.project_id), {
             "id": str(chat_msg.id),
             "chat_id": str(chat_id),
             "author_type": AuthorType.SYSTEM,
+            "author_id": str(actor_id) if actor_id else None,
             "author_slug": actor_slug,
             "content": chat_text,
             "created_at": chat_msg.created_at.isoformat() if chat_msg.created_at else now.isoformat(),
-        })
+        }, author_slug=actor_slug)
 
 
 def _task_out(t: Task, project_slug: str = "") -> dict:
@@ -178,9 +211,9 @@ def _task_out(t: Task, project_slug: str = "") -> dict:
         "priority": t.priority,
         "labels": t.labels or [],
         "assignee_id": str(t.assignee_id) if t.assignee_id else None,
-        "assignee": {"id": str(t.assignee.id), "slug": t.assignee.slug, "name": t.assignee.name} if t.assignee else None,
+        "assignee": _member_ref(t.assignee),
         "reviewer_id": str(t.reviewer_id) if t.reviewer_id else None,
-        "reviewer": {"id": str(t.reviewer.id), "slug": t.reviewer.slug, "name": t.reviewer.name} if t.reviewer else None,
+        "reviewer": _member_ref(t.reviewer),
         "watcher_ids": [str(w) for w in (t.watcher_ids or [])],
         "depends_on": [str(d) for d in (t.depends_on or [])],
         "position": t.position,
@@ -196,10 +229,10 @@ async def _get_task(task_id: str, db: AsyncSession) -> Task:
     result = await db.execute(
         select(Task).where(Task.id == uuid.UUID(task_id))
         .options(
-            selectinload(Task.steps), 
+            selectinload(Task.steps),
             joinedload(Task.project),
             joinedload(Task.assignee),
-            joinedload(Task.reviewer)
+            joinedload(Task.reviewer),
         )
     )
     task = result.scalar_one_or_none()
@@ -208,28 +241,37 @@ async def _get_task(task_id: str, db: AsyncSession) -> Task:
     return task
 
 
+async def _resolve_member(db: AsyncSession, member_id: str) -> Member:
+    """Resolve member by UUID. Raises 404 if not found."""
+    result = await db.execute(select(Member).where(Member.id == uuid.UUID(member_id)))
+    member = result.scalar_one_or_none()
+    if not member:
+        raise HTTPException(404, f"Member {member_id} not found")
+    return member
+
+
 # --- Endpoints ---
 
 @router.get("/tasks", response_model=list[TaskOut])
 async def list_tasks(
     project_id: Optional[str] = Query(None),
     status: Optional[str] = Query(None),
-    assignee: Optional[str] = Query(None),
+    assignee_id: Optional[str] = Query(None),
     label: Optional[str] = Query(None),
     db: AsyncSession = Depends(get_db),
 ):
     q = select(Task).options(
-        selectinload(Task.steps), 
+        selectinload(Task.steps),
         joinedload(Task.project),
         joinedload(Task.assignee),
-        joinedload(Task.reviewer)
+        joinedload(Task.reviewer),
     )
     if project_id:
         q = q.where(Task.project_id == uuid.UUID(project_id))
     if status:
         q = q.where(Task.status == status)
-    if assignee:
-        q = q.where(Task.assignee_id == uuid.UUID(assignee))
+    if assignee_id:
+        q = q.where(Task.assignee_id == uuid.UUID(assignee_id))
     if label:
         q = q.where(Task.labels.contains([label]))
     q = q.order_by(Task.position, Task.created_at)
@@ -250,16 +292,17 @@ async def create_task(
     current_member: Member = Depends(get_current_member),
     db: AsyncSession = Depends(get_db),
 ):
-    # Find project
     result = await db.execute(select(Project).where(Project.slug == project_slug))
     project = result.scalar_one_or_none()
     if not project:
         raise HTTPException(404, "Project not found")
 
-    # Increment task counter
     project.task_counter += 1
     number = project.task_counter
 
+    assignee_id = uuid.UUID(req.assignee_id) if req.assignee_id else None
+    reviewer_id = uuid.UUID(req.reviewer_id) if req.reviewer_id else None
+
     task = Task(
         project_id=project.id,
         parent_id=uuid.UUID(req.parent_id) if req.parent_id else None,
@@ -270,54 +313,43 @@ async def create_task(
         status=req.status,
         priority=req.priority,
         labels=req.labels,
-        assignee_id=uuid.UUID(req.assignee_id) if req.assignee_id else None,
-        reviewer_id=uuid.UUID(req.reviewer_id) if req.reviewer_id else None,
+        assignee_id=assignee_id,
+        reviewer_id=reviewer_id,
         depends_on=[uuid.UUID(d) for d in req.depends_on] if req.depends_on else [],
-        watcher_ids=[uuid.UUID(req.assignee_id)] if req.assignee_id else [],
+        watcher_ids=[assignee_id] if assignee_id else [],
     )
     db.add(task)
-    
-    # Create audit log
-    task_action = TaskAction(
-        task_id=task.id,
-        actor_id=current_member.id,
-        action=TaskActionType.CREATED
-    )
-    db.add(task_action)
-    
+
+    await _record_action(db, task, current_member, TaskActionType.CREATED)
+
     await db.commit()
-    await db.refresh(task)
-    # Load steps
     task_full = await _get_task(str(task.id), db)
-    
-    # Broadcast task.created event
+
+    # Broadcast
     from tracker.ws.manager import manager
-    task_data = {
+    key = f"{project.slug[:2].upper()}-{task.number}"
+    await manager.broadcast_task_event(str(project.id), WSEventType.TASK_CREATED, {
         "id": str(task.id),
         "project_id": str(project.id),
         "number": task.number,
-        "key": f"{project.slug[:2].upper()}-{task.number}",
+        "key": key,
         "title": task.title,
         "status": task.status,
-        "assignee_slug": task.assignee_slug,
-        "reviewer_slug": task.reviewer_slug,
-        "watchers": task.watchers or [],
-        "created_at": task.created_at.isoformat() if task.created_at else "",
-    }
-    await manager.broadcast_task_event(str(project.id), "task.created", task_data)
+        "assignee_id": str(assignee_id) if assignee_id else None,
+        "assignee": _member_ref(task_full.assignee),
+    })
 
     # System message
-    slug = project.slug
-    key = f"{slug[:2].upper()}-{task.number}"
     chat_text = f"{key} создана: {task.title}"
     task_text = f"Задача создана: {task.title}"
-    if task.assignee_slug:
-        chat_text += f" → @{task.assignee_slug}"
-        task_text += f". Назначена на @{task.assignee_slug}"
-    await _system_message(db, task_full, chat_text=chat_text, task_text=task_text, project_slug=slug)
+    if task_full.assignee:
+        chat_text += f" → @{task_full.assignee.slug}"
+        task_text += f". Назначена на @{task_full.assignee.slug}"
+    await _system_message(db, task_full, chat_text=chat_text, task_text=task_text,
+                          project_slug=project.slug, actor=current_member)
     await db.commit()
 
-    return _task_out(task_full, slug)
+    return _task_out(task_full, project.slug)
 
 
 @router.patch("/tasks/{task_id}", response_model=TaskOut)
@@ -332,209 +364,264 @@ async def update_task(
     prefix = slug[:2].upper() if slug else "XX"
     key = f"{prefix}-{task.number}"
     who = f"@{current_member.slug}"
+    now_str = datetime.datetime.now(datetime.timezone.utc).strftime("%H:%M UTC")
 
-    old_status = task.status
-    old_assignee_id = task.assignee_id
-
-    if req.title is not None:
+    # Track changes for audit + system messages
+    if req.title is not None and req.title != task.title:
+        await _record_action(db, task, current_member, TaskActionType.TITLE_CHANGED,
+                             "title", task.title, req.title)
         task.title = req.title
-    if req.description is not None:
+
+    if req.description is not None and req.description != task.description:
+        await _record_action(db, task, current_member, TaskActionType.DESCRIPTION_CHANGED,
+                             "description", task.description or "", req.description)
         task.description = req.description
+
     if req.type is not None:
         task.type = req.type
-    if req.status is not None:
-        task.status = req.status
-    if req.priority is not None:
-        task.priority = req.priority
-    if req.labels is not None:
-        task.labels = req.labels
-    if req.assignee_id is not None:
-        task.assignee_id = uuid.UUID(req.assignee_id) if req.assignee_id else None
-    if req.reviewer_id is not None:
-        task.reviewer_id = uuid.UUID(req.reviewer_id) if req.reviewer_id else None
-    if req.position is not None:
-        task.position = req.position
 
-    # System messages for important changes
-    import datetime
-    now_str = datetime.datetime.now(datetime.timezone.utc).strftime("%H:%M UTC")
-    if req.status is not None and req.status != old_status:
+    if req.status is not None and req.status != task.status:
+        old_status = task.status
+        await _record_action(db, task, current_member, TaskActionType.STATUS_CHANGED,
+                             "status", old_status, req.status)
+        task.status = req.status
         await _system_message(
             db, task,
             chat_text=f"{key}: {old_status} → {req.status}",
             task_text=f"{who} изменил статус: {old_status} → {req.status} ({now_str})",
-            project_slug=slug,
-            actor_id=str(current_member.id),
+            project_slug=slug, actor=current_member,
         )
-    if req.assignee_slug is not None and req.assignee_slug != old_assignee:
-        if req.assignee_slug:
-            await _system_message(
-                db, task,
-                chat_text=f"{key}: назначена на @{req.assignee_slug}",
-                task_text=f"{who} назначил задачу на @{req.assignee_slug} ({now_str})",
-                project_slug=slug,
-                actor_slug=current_member.slug,
-            )
-        else:
-            await _system_message(
-                db, task,
-                chat_text=f"{key}: исполнитель снят",
-                task_text=f"{who} снял исполнителя @{old_assignee} ({now_str})",
-                project_slug=slug,
-                actor_slug=current_member.slug,
-            )
+
+    if req.priority is not None and req.priority != task.priority:
+        old_priority = task.priority
+        await _record_action(db, task, current_member, TaskActionType.PRIORITY_CHANGED,
+                             "priority", old_priority, req.priority)
+        task.priority = req.priority
+
+    if req.labels is not None:
+        task.labels = req.labels
+
+    if req.assignee_id is not None:
+        old_assignee_id = task.assignee_id
+        new_assignee_id = uuid.UUID(req.assignee_id) if req.assignee_id else None
+        if new_assignee_id != old_assignee_id:
+            task.assignee_id = new_assignee_id
+            if new_assignee_id:
+                new_assignee = await _resolve_member(db, req.assignee_id)
+                await _record_action(db, task, current_member, TaskActionType.ASSIGNED,
+                                     "assignee_id", str(old_assignee_id) if old_assignee_id else None,
+                                     str(new_assignee_id))
+                await _system_message(
+                    db, task,
+                    chat_text=f"{key}: назначена на @{new_assignee.slug}",
+                    task_text=f"{who} назначил задачу на @{new_assignee.slug} ({now_str})",
+                    project_slug=slug, actor=current_member,
+                )
+                # Add to watchers
+                if new_assignee_id not in (task.watcher_ids or []):
+                    task.watcher_ids = (task.watcher_ids or []) + [new_assignee_id]
+            else:
+                await _record_action(db, task, current_member, TaskActionType.UNASSIGNED,
+                                     "assignee_id", str(old_assignee_id), None)
+                await _system_message(
+                    db, task,
+                    chat_text=f"{key}: исполнитель снят",
+                    task_text=f"{who} снял исполнителя ({now_str})",
+                    project_slug=slug, actor=current_member,
+                )
+
+    if req.reviewer_id is not None:
+        old_reviewer_id = task.reviewer_id
+        new_reviewer_id = uuid.UUID(req.reviewer_id) if req.reviewer_id else None
+        if new_reviewer_id != old_reviewer_id:
+            task.reviewer_id = new_reviewer_id
+            await _record_action(db, task, current_member, TaskActionType.REVIEWER_CHANGED,
+                                 "reviewer_id", str(old_reviewer_id) if old_reviewer_id else None,
+                                 str(new_reviewer_id) if new_reviewer_id else None)
+
+    if req.position is not None:
+        task.position = req.position
 
     await db.commit()
     await db.refresh(task)
-    
-    # Broadcast task.updated event
+
+    # Broadcast
     from tracker.ws.manager import manager
-    task_data = {
+    task_full = await _get_task(task_id, db)
+    await manager.broadcast_task_event(str(task.project_id), WSEventType.TASK_UPDATED, {
         "id": str(task.id),
         "status": task.status,
-        "assignee_slug": task.assignee_slug,
-        "updated_at": task.updated_at.isoformat() if task.updated_at else "",
-    }
-    await manager.broadcast_task_event(str(task.project_id), "task.updated", task_data)
-    
-    return _task_out(task, slug)
+        "assignee_id": str(task.assignee_id) if task.assignee_id else None,
+        "assignee": _member_ref(task_full.assignee),
+    })
+
+    return _task_out(task_full, slug)
 
 
 @router.delete("/tasks/{task_id}")
-async def delete_task(task_id: str, current_member: Member = Depends(get_current_member), db: AsyncSession = Depends(get_db)):
+async def delete_task(
+    task_id: str,
+    current_member: Member = Depends(get_current_member),
+    db: AsyncSession = Depends(get_db),
+):
     task = await _get_task(task_id, db)
     project_id = str(task.project_id)
-    task_data = {"id": str(task.id), "project_id": project_id}
+    await _record_action(db, task, current_member, TaskActionType.DELETED)
+    await db.commit()
     await db.delete(task)
     await db.commit()
     from tracker.ws.manager import manager
-    await manager.broadcast_task_event(project_id, "task.deleted", task_data)
+    await manager.broadcast_task_event(project_id, WSEventType.TASK_DELETED, {
+        "id": task_id, "project_id": project_id,
+    })
     return {"ok": True}
 
 
 @router.post("/tasks/{task_id}/take", response_model=TaskOut)
-async def take_task(task_id: str, current_member: Member = Depends(get_current_member), db: AsyncSession = Depends(get_db)):
-    """Atomically take a task — only if unassigned and in backlog/todo."""
-    slug = current_member.slug
+async def take_task(
+    task_id: str,
+    current_member: Member = Depends(get_current_member),
+    db: AsyncSession = Depends(get_db),
+):
+    """Take a task — only if unassigned and in backlog/todo."""
     task = await _get_task(task_id, db)
-    if task.assignee_slug:
-        raise HTTPException(409, f"Task already assigned to {task.assignee_slug}")
+    if task.assignee_id:
+        assignee_name = task.assignee.slug if task.assignee else str(task.assignee_id)
+        raise HTTPException(409, f"Task already assigned to {assignee_name}")
     if task.status not in (TaskStatus.BACKLOG, TaskStatus.TODO):
         raise HTTPException(409, f"Task status is {task.status}, expected backlog or todo")
-    task.assignee_slug = slug
+
+    task.assignee_id = current_member.id
     task.status = TaskStatus.IN_PROGRESS
-    # Add to watchers
-    if slug not in (task.watchers or []):
-        task.watchers = (task.watchers or []) + [slug]
-    await db.commit()
-    await db.refresh(task)
-    
-    # System message
+    if current_member.id not in (task.watcher_ids or []):
+        task.watcher_ids = (task.watcher_ids or []) + [current_member.id]
+
+    await _record_action(db, task, current_member, TaskActionType.ASSIGNED,
+                         "assignee_id", None, str(current_member.id))
+    await _record_action(db, task, current_member, TaskActionType.STATUS_CHANGED,
+                         "status", TaskStatus.BACKLOG, TaskStatus.IN_PROGRESS)
+
     proj_slug = task.project.slug if task.project else ""
-    prefix = proj_slug[:2].upper() if proj_slug else "XX"
-    key = f"{prefix}-{task.number}"
-    import datetime
-    now_str = datetime.datetime.now(datetime.timezone.utc).strftime("%H:%M UTC")
+    key = f"{proj_slug[:2].upper()}-{task.number}"
     await _system_message(
         db, task,
-        chat_text=f"{key}: @{slug} взял в работу",
-        task_text=f"@{slug} взял задачу в работу ({now_str})",
-        project_slug=proj_slug,
-        actor_slug=slug,
+        chat_text=f"{key}: @{current_member.slug} взял в работу",
+        task_text=f"@{current_member.slug} взял задачу в работу",
+        project_slug=proj_slug, actor=current_member,
     )
     await db.commit()
 
-    # Broadcast task.assigned event
     from tracker.ws.manager import manager
-    task_data = {
+    await manager.broadcast_task_event(str(task.project_id), WSEventType.TASK_ASSIGNED, {
         "id": str(task.id),
-        "assignee_slug": slug,
-        "assigner_slug": slug,  # self-assigned
-        "assigned_at": task.updated_at.isoformat() if task.updated_at else "",
-    }
-    await manager.broadcast_task_event(str(task.project_id), "task.assigned", task_data)
-    
-    return _task_out(task, proj_slug)
+        "assignee_id": str(current_member.id),
+        "assignee": _member_ref(current_member),
+    })
+
+    task_full = await _get_task(task_id, db)
+    return _task_out(task_full, proj_slug)
 
 
 @router.post("/tasks/{task_id}/reject")
-async def reject_task(task_id: str, req: RejectRequest, current_member: Member = Depends(get_current_member), db: AsyncSession = Depends(get_db)):
-    """Reject a task with reason — unassign and return to todo."""
+async def reject_task(
+    task_id: str,
+    req: RejectRequest,
+    current_member: Member = Depends(get_current_member),
+    db: AsyncSession = Depends(get_db),
+):
+    """Reject a task — unassign and return to backlog."""
     task = await _get_task(task_id, db)
-    old_assignee = task.assignee_slug
-    task.assignee_slug = None
+    old_assignee_id = task.assignee_id
+    task.assignee_id = None
     task.status = TaskStatus.BACKLOG
-    # Add rejection comment
-    if old_assignee:
-        comment = Message(
-            task_id=task.id,
-            author_type=AuthorType.SYSTEM,
-            author_slug=old_assignee,
-            content=f"Задача отклонена: {req.reason}",
-            mentions=[],
-        )
-        db.add(comment)
+
+    await _record_action(db, task, current_member, TaskActionType.UNASSIGNED,
+                         "assignee_id", str(old_assignee_id) if old_assignee_id else None, None)
+    await _record_action(db, task, current_member, TaskActionType.STATUS_CHANGED,
+                         "status", task.status, TaskStatus.BACKLOG)
+
+    comment = Message(
+        task_id=task.id,
+        author_type=AuthorType.SYSTEM,
+        author_id=current_member.id,
+        content=f"Задача отклонена: {req.reason}",
+        mentions=[],
+    )
+    db.add(comment)
     await db.commit()
+
     from tracker.ws.manager import manager
-    await manager.broadcast_task_event(str(task.project_id), "task.updated", {
-        "id": str(task.id), "status": TaskStatus.BACKLOG, "assignee_slug": None,
+    await manager.broadcast_task_event(str(task.project_id), WSEventType.TASK_UPDATED, {
+        "id": str(task.id), "status": TaskStatus.BACKLOG, "assignee_id": None, "assignee": None,
     })
-    return {"ok": True, "reason": req.reason, "old_assignee": old_assignee}
+    return {"ok": True, "reason": req.reason}
 
 
 @router.post("/tasks/{task_id}/assign", response_model=TaskOut)
-async def assign_task(task_id: str, req: AssignRequest, current_member: Member = Depends(get_current_member), db: AsyncSession = Depends(get_db)):
-    """Assign task to a member."""
-    # Verify assignee exists
-    result = await db.execute(select(Member).where(Member.slug == req.assignee_slug))
-    if not result.scalar_one_or_none():
-        raise HTTPException(404, f"Member {req.assignee_slug} not found")
+async def assign_task(
+    task_id: str,
+    req: AssignRequest,
+    current_member: Member = Depends(get_current_member),
+    db: AsyncSession = Depends(get_db),
+):
+    """Assign task to a member by UUID."""
+    assignee = await _resolve_member(db, req.assignee_id)
     task = await _get_task(task_id, db)
-    task.assignee_slug = req.assignee_slug
-    if req.assignee_slug not in (task.watchers or []):
-        task.watchers = (task.watchers or []) + [req.assignee_slug]
-    await db.commit()
-    await db.refresh(task)
-    
-    # System message
+    old_assignee_id = task.assignee_id
+
+    task.assignee_id = assignee.id
+    if assignee.id not in (task.watcher_ids or []):
+        task.watcher_ids = (task.watcher_ids or []) + [assignee.id]
+
+    await _record_action(db, task, current_member, TaskActionType.ASSIGNED,
+                         "assignee_id", str(old_assignee_id) if old_assignee_id else None,
+                         str(assignee.id))
+
     proj_slug = task.project.slug if task.project else ""
-    prefix = proj_slug[:2].upper() if proj_slug else "XX"
-    key = f"{prefix}-{task.number}"
+    key = f"{proj_slug[:2].upper()}-{task.number}"
     await _system_message(
         db, task,
-        chat_text=f"{key}: назначена на @{req.assignee_slug}",
-        task_text=f"Задача назначена на @{req.assignee_slug}",
-        project_slug=proj_slug,
+        chat_text=f"{key}: назначена на @{assignee.slug}",
+        task_text=f"@{current_member.slug} назначил задачу на @{assignee.slug}",
+        project_slug=proj_slug, actor=current_member,
     )
     await db.commit()
 
-    # Broadcast task.assigned event  
     from tracker.ws.manager import manager
-    task_data = {
+    await manager.broadcast_task_event(str(task.project_id), WSEventType.TASK_ASSIGNED, {
         "id": str(task.id),
-        "assignee_slug": req.assignee_slug,
-        "assigner_slug": "admin",  # TODO: get from auth context
-        "assigned_at": task.updated_at.isoformat() if task.updated_at else "",
-    }
-    await manager.broadcast_task_event(str(task.project_id), "task.assigned", task_data)
-    
-    return _task_out(task, proj_slug)
+        "assignee_id": str(assignee.id),
+        "assignee": _member_ref(assignee),
+    })
+
+    task_full = await _get_task(str(task.id), db)
+    return _task_out(task_full, proj_slug)
 
 
 @router.post("/tasks/{task_id}/watch")
-async def watch_task(task_id: str, current_member: Member = Depends(get_current_member), db: AsyncSession = Depends(get_db)):
-    slug = current_member.slug
+async def watch_task(
+    task_id: str,
+    current_member: Member = Depends(get_current_member),
+    db: AsyncSession = Depends(get_db),
+):
     task = await _get_task(task_id, db)
-    if slug not in (task.watchers or []):
-        task.watchers = (task.watchers or []) + [slug]
+    if current_member.id not in (task.watcher_ids or []):
+        task.watcher_ids = (task.watcher_ids or []) + [current_member.id]
+        await _record_action(db, task, current_member, TaskActionType.WATCHER_ADDED,
+                             "watcher_ids", None, str(current_member.id))
         await db.commit()
-    return {"ok": True, "watchers": task.watchers}
+    return {"ok": True, "watcher_ids": [str(w) for w in (task.watcher_ids or [])]}
 
 
 @router.delete("/tasks/{task_id}/watch")
-async def unwatch_task(task_id: str, current_member: Member = Depends(get_current_member), db: AsyncSession = Depends(get_db)):
-    slug = current_member.slug
+async def unwatch_task(
+    task_id: str,
+    current_member: Member = Depends(get_current_member),
+    db: AsyncSession = Depends(get_db),
+):
     task = await _get_task(task_id, db)
-    task.watchers = [w for w in (task.watchers or []) if w != slug]
+    task.watcher_ids = [w for w in (task.watcher_ids or []) if w != current_member.id]
+    await _record_action(db, task, current_member, TaskActionType.WATCHER_REMOVED,
+                         "watcher_ids", str(current_member.id), None)
     await db.commit()
-    return {"ok": True, "watchers": task.watchers}
+    return {"ok": True, "watcher_ids": [str(w) for w in (task.watcher_ids or [])]}

src/tracker/ws/handler.py

@@ -163,6 +163,7 @@ async def _authenticate(ws: WebSocket, token: str, on_behalf_of: str | None = No
         client = ConnectedClient(
             ws=ws,
             session_id=session_id,
+            member_id=str(member.id),
             member_slug=effective_slug,
             member_type=effective_type,
             chat_listen=chat_listen,

src/tracker/ws/manager.py

@@ -16,8 +16,9 @@ logger = logging.getLogger("tracker.ws")
 class ConnectedClient:
     ws: WebSocket
     session_id: str  # unique per connection
-    member_slug: str
-    member_type: str  # human | agent | bridge
+    member_id: str | None = None  # UUID as string
+    member_slug: str = ""
+    member_type: str = ""  # human | agent | bridge
     chat_listen: str = ListenMode.ALL
     task_listen: str = ListenMode.ALL
     subscribed_projects: set[str] = field(default_factory=set)
@@ -118,9 +119,9 @@ class ConnectionManager:
 
     async def broadcast_task_event(self, project_id: str, event_type: str, data: dict):
         """Broadcast task events. Humans get everything, agents filtered."""
-        assignee = data.get("assignee_slug")
-        reviewer = data.get("reviewer_slug")
-        watchers = data.get("watchers", [])
+        assignee_id = data.get("assignee_id")
+        reviewer_id = data.get("reviewer_id")
+        watcher_ids = data.get("watcher_ids", [])
         payload = {"type": event_type, "data": data}
 
         for session_id, client in list(self.sessions.items()):
@@ -136,7 +137,11 @@ class ConnectionManager:
             if client.task_listen == ListenMode.ALL:
                 await self.send_to_session(session_id, payload)
                 continue
-            if client.member_slug in (assignee, reviewer) or client.member_slug in watchers:
+            # For "mentions" mode: check if agent is assignee/reviewer/watcher
+            if client.member_id and (
+                client.member_id in (assignee_id, reviewer_id) or
+                client.member_id in watcher_ids
+            ):
                 await self.send_to_session(session_id, payload)
 
     async def broadcast_all(self, data: dict, exclude_slug: str | None = None):