Add in-progress status tracking for features

Implements feature locking to prevent multiple agent sessions from working
on the same feature simultaneously. This is essential for parallel agent
execution.

Database changes:
- Add `in_progress` boolean column to Feature model
- Add migration function to handle existing databases

MCP Server tools:
- Add `feature_mark_in_progress` - lock feature when starting work
- Add `feature_clear_in_progress` - unlock feature when abandoning
- Update `feature_get_next` to skip in-progress features
- Update `feature_get_stats` to include in_progress count
- Update `feature_mark_passing` and `feature_skip` to clear in_progress

Backend updates:
- Update progress.py to track and display in_progress count
- Update features router to properly categorize in-progress features
- Update WebSocket to broadcast in_progress in progress updates
- Add in_progress to FeatureResponse schema

Frontend updates:
- Add in_progress to TypeScript types (Feature, ProjectStats, WSProgressMessage)
- Update useWebSocket hook to track in_progress state

Prompt template:
- Add instructions for agents to mark features in-progress immediately
- Document new MCP tools in allowed tools section

Also fixes spec_chat_session.py to use absolute project path instead of
relative path for consistency with CLI behavior.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

server/websocket.py

@@ -117,21 +117,24 @@ async def poll_progress(websocket: WebSocket, project_name: str):
     project_dir = _get_generations_dir() / project_name
     count_passing_tests = _get_count_passing_tests()
     last_passing = -1
+    last_in_progress = -1
     last_total = -1
 
     while True:
         try:
-            passing, total = count_passing_tests(project_dir)
+            passing, in_progress, total = count_passing_tests(project_dir)
 
             # Only send if changed
-            if passing != last_passing or total != last_total:
+            if passing != last_passing or in_progress != last_in_progress or total != last_total:
                 last_passing = passing
+                last_in_progress = in_progress
                 last_total = total
                 percentage = (passing / total * 100) if total > 0 else 0
 
                 await websocket.send_json({
                     "type": "progress",
                     "passing": passing,
+                    "in_progress": in_progress,
                     "total": total,
                     "percentage": round(percentage, 1),
                 })
@@ -204,11 +207,12 @@ async def project_websocket(websocket: WebSocket, project_name: str):
 
         # Send initial progress
         count_passing_tests = _get_count_passing_tests()
-        passing, total = count_passing_tests(project_dir)
+        passing, in_progress, total = count_passing_tests(project_dir)
         percentage = (passing / total * 100) if total > 0 else 0
         await websocket.send_json({
             "type": "progress",
             "passing": passing,
+            "in_progress": in_progress,
             "total": total,
             "percentage": round(percentage, 1),
         })