Add per-workstream task counts to state summary and dashboard

API:
- WorkstreamWithTaskCounts schema extends WorkstreamRead with
  tasks_total/todo/in_progress/blocked/done fields
- /state/summary now includes these counts in open_workstreams via
  a single extra GROUP BY query (workstream_id, status)

Dashboard:
- Replace domain workstream-count bar with a horizontal stacked
  progress bar per workstream (done/in-progress/blocked/todo)
- Workstreams with no tasks show "no tasks yet" annotation
- Workstreams with tasks show "X/N done" label after the bar
- Sorted by domain then title so domains group naturally

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/schemas/state.py

@@ -6,7 +6,7 @@ from api.schemas.decision import DecisionRead
 from api.schemas.progress_event import ProgressEventRead
 from api.schemas.task import TaskRead
 from api.schemas.topic import TopicWithWorkstreams
-from api.schemas.workstream import WorkstreamRead
+from api.schemas.workstream import WorkstreamWithTaskCounts
 
 
 class TopicTotals(BaseModel):
@@ -55,4 +55,4 @@ class StateSummary(BaseModel):
     blocking_decisions: list[DecisionRead]
     blocked_tasks: list[TaskRead]
     recent_progress: list[ProgressEventRead]
-    open_workstreams: list[WorkstreamRead]
+    open_workstreams: list[WorkstreamWithTaskCounts]