fix(chat): tighten runtime internal-message filtering and add targeted tests (#891)

tests/unit/chat-internal-message-filter.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest';
+import { isInternalMessage } from '@/stores/chat/helpers';
+
+describe('chat internal message filter', () => {
+  it('filters runtime system injection bundle like async exec completion payload', () => {
+    const content = [
+      'System (untrusted): [2026-04-22 10:06:24 GMT+8] Exec completed (nimbler, code 0) ...',
+      'An async command you ran earlier has completed. The result is shown in the system messages above. Handle the result internally. Do not relay it to the user unless explicitly requested.',
+      'Current time: Wednesday, April 22nd, 2026 - 10:06 (Asia/Shanghai) / 2026-04-22 02:06 UTC',
+    ].join('\n\n');
+
+    expect(isInternalMessage({ role: 'user', content })).toBe(true);
+  });
+
+  it('filters standalone current-time runtime ping', () => {
+    const content = 'Current time: Wednesday, April 22nd, 2026 - 10:06 (Asia/Shanghai) / 2026-04-22 02:06 UTC';
+
+    expect(isInternalMessage({ role: 'assistant', content })).toBe(true);
+  });
+
+  it('does not filter normal user message that starts with current time', () => {
+    const content = 'Current time: 北京现在几点？';
+
+    expect(isInternalMessage({ role: 'user', content })).toBe(false);
+  });
+
+  it('does not filter normal assistant text that mentions async completion phrase only', () => {
+    const content = 'The sentence "An async command you ran earlier has completed" is just an example in docs.';
+
+    expect(isInternalMessage({ role: 'assistant', content })).toBe(false);
+  });
+});