sync: update heartbeat, logs, add agent-browser skill, remove gitea skill

HEARTBEAT.md

@@ -3,6 +3,7 @@
 ## Check: Email (Lightweight)
 - Log: Append timestamp to `~/.openclaw/workspace/logs/email_checks.log` before checking
 - Run: ~/.local/bin/himalaya envelope list --page-size 20
-- If unread emails found, report count and subjects
+- **Only report UNREAD emails** (flagged with `*` in FLAGS column)
+- Read emails: completely ignore, do not mention at all in response
 - No Ollama analysis (too slow for heartbeat)
-- Remind user to manually process if count > 0
+- Remind user to manually process unread emails if count > 0