feat: agent coordination system (workflows, locks, components, messages)

Adds /api/coord/* endpoints for real-time cross-session coordination:
- coord_workflows: named units of work per project
- coord_work_items: tasks within workflows with dependency chains
- coord_session_locks: exclusive resource locks with auto-expiry (TTL)
- coord_component_states: live component state per project (upsert)
- coord_messages: cross-session messaging and broadcasts
- /api/coord/status: cross-project snapshot endpoint

Replaces PROJECT_STATE.md as the coordination layer for Claude sessions.

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

api/schemas/coord_component_state.py

@@ -0,0 +1,30 @@
+"""Pydantic schemas for CoordComponentState."""
+
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+class CoordComponentStateUpsert(BaseModel):
+    """Input schema for upserting a component state."""
+
+    state: str = Field(..., description="State: deployed, building, stable, broken, unknown", max_length=50)
+    version: Optional[str] = Field(None, description="Version string or git SHA", max_length=100)
+    notes: Optional[str] = Field(None, description="Freeform notes")
+    updated_by: str = Field(..., description="Session performing this update", max_length=200)
+
+
+class CoordComponentStateResponse(BaseModel):
+    """Output schema for a component state."""
+
+    project_key: str
+    component: str
+    state: str
+    version: Optional[str]
+    notes: Optional[str]
+    updated_by: str
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = {"from_attributes": True}