Enable nudge digestion in the deployed config

Turns on the existing digest path on homesrv: a 30m batching window, at most 5
items per flush, and a severity ceiling of 2 so anything more urgent still
goes out immediately instead of waiting for the batch.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X5JApcrCRVGmqrxnhynSik

deploy/mavend.json

@@ -18,6 +18,13 @@
     "chat_id": "${TELEGRAM_CHAT_ID}"
   },
 
+  "digest": {
+    "enabled": true,
+    "window": "30m",
+    "max_items": 5,
+    "severity_ceiling": 2
+  },
+
   "nexus":  { "url": "http://nexus:9740" },
   "praxis": { "url": "http://praxis:8989" },
   "hexis":  { "url": "http://hexis:9741" },