feat(grid-agent): supervise grid sessions (#121)

config/grid-agent.example.json

@@ -25,5 +25,12 @@
   "storage_path": "data/grid-agent",
   "behavior": {
     "heartbeat_seconds": 30
+  },
+  "reconnect": {
+    "initial_delay_milliseconds": 1000,
+    "maximum_delay_seconds": 60,
+    "stable_reset_seconds": 120,
+    "jitter_basis_points": 2000,
+    "offline_work_capacity": 128
   }
 }