feat(companion): add reconnect resilience

docs/plans/state.json

@@ -6699,10 +6699,28 @@
         "docs/plans/state.json"
       ],
       "test_status": "pnpm test:run src/automation/reactions.test.ts src/config/schema.test.ts src/daemon/routing.test.ts passing"
+    },
+    "deeper-surfaces-phase3-companion-reconnect": {
+      "status": "completed",
+      "date": "2026-02-25",
+      "updated": "2026-02-25",
+      "summary": "Hardened companion runtime connectivity with auto-reconnect support, connection event subscriptions, CLI re-registration/heartbeat resilience, and updated protocol/architecture notes plus targeted tests.",
+      "files_modified": [
+        "src/companion/runtimeClient.ts",
+        "src/companion/runtimeClient.test.ts",
+        "src/companion/index.ts",
+        "src/cli/companion.ts",
+        "src/cli/companion.test.ts",
+        "docs/api/PROTOCOL.md",
+        "docs/architecture/AGENT_DIAGRAM.md",
+        "docs/architecture/GATEWAY_SESSIONS_AND_QUEUE.md",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/companion/runtimeClient.test.ts src/cli/companion.test.ts passing"
     }
   },
   "overall_progress": {
-    "total_test_count": 2018,
+    "total_test_count": 2020,
     "all_tests_passing": true,
     "p0_completion": "3/3 (100%)",
     "p1_completion": "4/4 (100%)",