fix: persistent daemon startup, plugin integration, mobile fallback

- Hook handler now loads .env.daemon for proper config (plugin URL/secret, bot user ID)
- Hook logs to /tmp/status-watcher.log instead of /dev/null
- Added .env.daemon config file (.gitignored - contains tokens)
- Added start-daemon.sh convenience script
- Plugin mode: mobile fallback updates post message field with formatted markdown
- Fixed unbounded lines array in status-watcher (capped at 50)
- Added session marker to formatter output for restart recovery
- Go plugin: added updatePostMessageForMobile() for dual-render strategy
  (webapp gets custom React component, mobile gets markdown in message field)

Fixes: daemon silently dying, no plugin connection, mobile showing blank posts

.gitignore

@@ -3,3 +3,4 @@ coverage/
 *.log
 plugin/server/dist/
 plugin/webapp/node_modules/
+.env.daemon