feat: Add epic_close MCP tool

- New epic_close(id) function to mark epics as completed
- Added tool definition and handler
- Usage: epic_close({ id: 'CF-E1' })

Task: CF-258

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

src/tools/epics.ts

@@ -209,3 +209,30 @@ export async function epicUnassign(task_id: string): Promise<string> {
 
   return `Unassigned ${task_id} from its epic`;
 }
+
+/**
+ * Close an epic (mark as completed)
+ */
+export async function epicClose(id: string): Promise<string> {
+  // Verify epic exists
+  const epic = await queryOne<{ id: string; title: string; status: string }>(
+    `SELECT id, title, status FROM epics WHERE id = $1`,
+    [id]
+  );
+
+  if (!epic) {
+    return `Epic not found: ${id}`;
+  }
+
+  if (epic.status === 'completed') {
+    return `Epic already completed: ${id}`;
+  }
+
+  // Update epic status
+  await execute(
+    `UPDATE epics SET status = 'completed', updated_at = NOW() WHERE id = $1`,
+    [id]
+  );
+
+  return `Closed: ${id} (${epic.title})`;
+}

src/tools/index.ts

@@ -197,6 +197,17 @@ export const toolDefinitions = [
       required: ['task_id', 'epic_id'],
     },
   },
+  {
+    name: 'epic_close',
+    description: 'Close an epic (mark as completed)',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        id: { type: 'string', description: 'Epic ID to close (e.g., VPN-E1, ST-E3)' },
+      },
+      required: ['id'],
+    },
+  },
 
   // Delegation Tools
   {