fix: reduce log noise for node disconnect/late invoke errors (#1607)

* fix: reduce log noise for node disconnect/late invoke errors

- Handle both 'node not connected' and 'node disconnected' errors at info level
- Return success with late:true for unknown invoke IDs instead of error
- Add 30-second throttle to skills change listener to prevent rapid-fire probes
- Add tests for isNodeUnavailableError and late invoke handling

* fix: clean up skills refresh timer and listener on shutdown

Store the return value from registerSkillsChangeListener() and call it
on gateway shutdown. Also clear any pending refresh timer. This follows
the same pattern used for agentUnsub and heartbeatUnsub.

* refactor: simplify KISS/YAGNI - inline checks, remove unit tests for internal utilities

* fix: reduce gateway log noise (#1607) (thanks @petter-b)

* test: align agent id casing expectations (#1607)

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

CHANGELOG.md

@@ -12,7 +12,7 @@ Docs: https://docs.clawd.bot
 ### Fixes
 - Web UI: hide internal `message_id` hints in chat bubbles.
 - Heartbeat: normalize target identifiers for consistent routing.
-- TUI: unify reasoning tag stripping so `<final>` wrappers stay hidden. (#1613) Thanks @kyleok.
+- Gateway: reduce log noise for late invokes + remote node probes; debounce skills refresh. (#1607) Thanks @petter-b.
 
 ## 2026.1.23-1