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>

api/database.py

@@ -28,6 +28,7 @@ class Feature(Base):
     description = Column(Text, nullable=False)
     steps = Column(JSON, nullable=False)  # Stored as JSON array
     passes = Column(Boolean, default=False, index=True)
+    in_progress = Column(Boolean, default=False, index=True)
 
     def to_dict(self) -> dict:
         """Convert feature to dictionary for JSON serialization."""
@@ -39,6 +40,7 @@ class Feature(Base):
             "description": self.description,
             "steps": self.steps,
             "passes": self.passes,
+            "in_progress": self.in_progress,
         }
 
 
@@ -56,6 +58,21 @@ def get_database_url(project_dir: Path) -> str:
     return f"sqlite:///{db_path.as_posix()}"
 
 
+def _migrate_add_in_progress_column(engine) -> None:
+    """Add in_progress column to existing databases that don't have it."""
+    from sqlalchemy import text
+
+    with engine.connect() as conn:
+        # Check if column exists
+        result = conn.execute(text("PRAGMA table_info(features)"))
+        columns = [row[1] for row in result.fetchall()]
+
+        if "in_progress" not in columns:
+            # Add the column with default value
+            conn.execute(text("ALTER TABLE features ADD COLUMN in_progress BOOLEAN DEFAULT 0"))
+            conn.commit()
+
+
 def create_database(project_dir: Path) -> tuple:
     """
     Create database and return engine + session maker.
@@ -69,6 +86,10 @@ def create_database(project_dir: Path) -> tuple:
     db_url = get_database_url(project_dir)
     engine = create_engine(db_url, connect_args={"check_same_thread": False})
     Base.metadata.create_all(bind=engine)
+
+    # Migrate existing databases to add in_progress column
+    _migrate_add_in_progress_column(engine)
+
     SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
     return engine, SessionLocal