fix(whatsapp): sandbox chromium by default

docs/plans/state.json

@@ -2496,6 +2496,22 @@
         "docs/plans/analysis/2026-02-16-codebase-audit-report.md"
       ],
       "test_status": "pnpm test:run src/gateway/server.test.ts src/config/schema.test.ts + pnpm typecheck passing"
+    },
+    "audit-followup-whatsapp-sandbox-default": {
+      "status": "completed",
+      "date": "2026-02-16",
+      "updated": "2026-02-16",
+      "summary": "Hardened WhatsApp adapter Chromium launch defaults: sandbox enabled by default, with explicit opt-in no-sandbox mode via whatsapp.no_sandbox. Added adapter and schema regression tests.",
+      "files_modified": [
+        "src/channels/whatsapp/adapter.ts",
+        "src/channels/whatsapp/adapter.test.ts",
+        "src/config/schema.ts",
+        "src/config/schema.test.ts",
+        "src/daemon/channels.ts",
+        "README.md",
+        "docs/plans/analysis/2026-02-16-codebase-audit-report.md"
+      ],
+      "test_status": "pnpm test:run src/channels/whatsapp/adapter.test.ts src/config/schema.test.ts + pnpm typecheck passing"
     }
   },
   "overall_progress": {