Update bot user ID and model name in configuration files; enhance outage recovery reporting

config.example.json

@@ -4,7 +4,7 @@
   "agent_file": "agents/stack-support.agent.md",
   "runbook_file": "docs/stack-support-runbook.md",
   "claude_bin": "/home/paul/.local/bin/claude",
-  "claude_model": "claude-opus-4-8",
+  "claude_model": "claude-sonnet-4-6",
   "claude_extra_args": [],
   "agent_timeout_seconds": 1800,
 
@@ -22,7 +22,7 @@
 
   "matrix": {
     "homeserver": "https://matrix.semprini.me",
-    "user_id": "@claude-code:semprini.me",
+    "user_id": "@maintainer-bot:semprini.me",
     "access_token": "FILLED_BY_register-matrix-bot.sh",
     "room_id": "FILLED_BY_register-matrix-bot.sh",
     "admin_user_id": "@paul:semprini.me"