feat(chat): add /stop cancellation command across gateway and telegram

src/gateway/handlers/agent.test.ts

@@ -36,6 +36,7 @@ describe('createAgentHandlers command fast-path', () => {
     setBusy: vi.fn(),
     setOnToolUse: vi.fn(),
     isBusy: vi.fn(() => false),
+    cancel: vi.fn(() => true),
   };
 
   const sessionManager = {
@@ -219,6 +220,26 @@ describe('createAgentHandlers command fast-path', () => {
     expect(((sent[0] as GatewayEvent).data as { content: string }).content).toContain('Reset default to: anthropic/claude-sonnet-4');
   });
 
+  it('handles /stop command via fast-path and requests cancellation', async () => {
+    const sent: OutboundMessage[] = [];
+    const send = vi.fn((msg: OutboundMessage) => sent.push(msg));
+    const req: GatewayRequest = {
+      id: 12,
+      method: 'agent.send',
+      params: {
+        message: '/stop',
+        connectionId: 'conn-1',
+        metadata: { isCommand: true, command: 'stop' },
+      },
+    };
+
+    await handlers['agent.send'](req, send);
+
+    expect(sessionBridge.cancel).toHaveBeenCalledWith('conn-1');
+    expect(mockAgent.process).not.toHaveBeenCalled();
+    expect(((sent[0] as GatewayEvent).data as { content: string }).content).toContain('Cancellation requested');
+  });
+
   it('falls through to agent.process for unknown commands', async () => {
     const sent: OutboundMessage[] = [];
     const send = vi.fn((msg: OutboundMessage) => sent.push(msg));

src/gateway/handlers/agent.ts

@@ -294,6 +294,12 @@ export function createAgentHandlers(deps: AgentHandlerDeps) {
                   }
                   return 'Session reset.';
                 },
+                cancelRun: () => {
+                  const cancelled = deps.sessionBridge.cancel(connectionId);
+                  return cancelled
+                    ? 'Cancellation requested. The active operation will stop at the next safe point.'
+                    : 'No active operation to cancel.';
+                },
                 getApprovals: () => {
                   if (!deps.hookEngine) {
                     return 'Approval gates are not enabled in this runtime.';