Add fleet control: service configs, replica floors, monitor, pause/restart

Central fleet.json sets min/max copies. Tree-node keepFloor respawns
until three healthy unpaused replicas remain. CLI and loopback UI
pause, resume, stop, and restart instances that fail health checks.

packages/verae-fleet/services/archive-aggregator.json

@@ -0,0 +1,16 @@
+{
+  "id": "archive-aggregator",
+  "title": "Archive reply aggregator",
+  "kind": "nats-worker",
+  "package": "verae-archive-aggregator",
+  "role": "archive-aggregator",
+  "managed": true,
+  "runtime": "query fan-out + merge",
+  "health": { "type": "http", "path": "/health", "timeoutMs": 800 },
+  "ports": { "healthBase": 13400 },
+  "nats": {
+    "in": ["verae.archive.reply.*"],
+    "out": ["verae.archive.query"]
+  },
+  "notes": "Broadcast archive.query (no queue group). kinds may include tree."
+}