feat: component-separated logging with session context and filtering (#7991)

* feat: component-separated logging with session context and filtering

Phase 1 — Gateway log isolation:
- gateway.log now only receives records from gateway.* loggers
  (platform adapters, session management, slash commands, delivery)
- agent.log remains the catch-all (all components)
- errors.log remains WARNING+ catch-all
- Moved gateway.log handler creation from gateway/run.py into
  hermes_logging.setup_logging(mode='gateway') with _ComponentFilter

Phase 2 — Session ID injection:
- Added set_session_context(session_id) / clear_session_context() API
  using threading.local() for per-thread session tracking
- _SessionFilter enriches every log record with session_tag attribute
- Log format: '2026-04-11 10:23:45 INFO [session_id] logger.name: msg'
- Session context set at start of run_conversation() in run_agent.py
- Thread-isolated: gateway conversations on different threads don't leak

Phase 3 — Component filtering in hermes logs:
- Added --component flag: hermes logs --component gateway|agent|tools|cli|cron
- COMPONENT_PREFIXES maps component names to logger name prefixes
- Works with all existing filters (--level, --session, --since, -f)
- Logger name extraction handles both old and new log formats

Files changed:
- hermes_logging.py: _SessionFilter, _ComponentFilter, COMPONENT_PREFIXES,
  set/clear_session_context(), gateway.log creation in setup_logging()
- gateway/run.py: removed redundant gateway.log handler (now in hermes_logging)
- run_agent.py: set_session_context() at start of run_conversation()
- hermes_cli/logs.py: --component filter, logger name extraction
- hermes_cli/main.py: --component argument on logs subparser

Addresses community request for component-separated, filterable logging.
Zero changes to existing logger names — __name__ already provides hierarchy.

* fix: use LogRecord factory instead of per-handler _SessionFilter

The _SessionFilter approach required attaching a filter to every handler
we create. Any handler created outside our _add_rotating_handler (like
the gateway stderr handler, or third-party handlers) would crash with
KeyError: 'session_tag' if it used our format string.

Replace with logging.setLogRecordFactory() which injects session_tag
into every LogRecord at creation time — process-global, zero per-handler
wiring needed. The factory is installed at import time (before
setup_logging) so session_tag is available from the moment hermes_logging
is imported.

- Idempotent: marker attribute prevents double-wrapping on module reload
- Chains with existing factory: won't break third-party record factories
- Removes _SessionFilter from _add_rotating_handler and setup_verbose_logging
- Adds tests: record factory injection, idempotency, arbitrary handler compat

run_agent.py

@@ -7529,6 +7529,11 @@ class AIAgent:
         # Installed once, transparent when streams are healthy, prevents crash on write.
         _install_safe_stdio()
 
+        # Tag all log records on this thread with the session ID so
+        # ``hermes logs --session <id>`` can filter a single conversation.
+        from hermes_logging import set_session_context
+        set_session_context(self.session_id)
+
         # If the previous turn activated fallback, restore the primary
         # runtime so this turn gets a fresh attempt with the preferred model.
         # No-op when _fallback_activated is False (gateway, first turn, etc.).