feat: Add project lock mechanism for session exclusivity

New MCP tools:
- project_lock: Lock a project for exclusive session access
- project_unlock: Release a project lock
- project_lock_status: Check lock status for project(s)

Features:
- Automatic lock expiration (default 2h)
- Session ownership verification
- Force unlock option for emergencies
- Lock extension on re-lock by same session

Migration 004: project_locks table with expiry tracking

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

src/tools/index.ts

@@ -233,4 +233,43 @@ export const toolDefinitions = [
       },
     },
   },
+
+  // Project Lock Tools
+  {
+    name: 'project_lock',
+    description: 'Lock a project for exclusive session access. Prevents other sessions from working on it.',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        project: { type: 'string', description: 'Project key (e.g., VPN, ST)' },
+        session_id: { type: 'string', description: 'Unique session identifier' },
+        duration_minutes: { type: 'number', description: 'Lock duration in minutes (default: 120)' },
+        reason: { type: 'string', description: 'Optional reason for locking' },
+      },
+      required: ['project', 'session_id'],
+    },
+  },
+  {
+    name: 'project_unlock',
+    description: 'Release a project lock',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        project: { type: 'string', description: 'Project key to unlock' },
+        session_id: { type: 'string', description: 'Session ID (must match lock owner unless force=true)' },
+        force: { type: 'boolean', description: 'Force unlock even if owned by different session' },
+      },
+      required: ['project'],
+    },
+  },
+  {
+    name: 'project_lock_status',
+    description: 'Check lock status for a project or all projects',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        project: { type: 'string', description: 'Project key (optional, shows all if omitted)' },
+      },
+    },
+  },
 ];