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

hermes_cli/main.py

@@ -4338,6 +4338,7 @@ def cmd_logs(args):
         level=getattr(args, "level", None),
         session=getattr(args, "session", None),
         since=getattr(args, "since", None),
+        component=getattr(args, "component", None),
     )
 
 
@@ -5737,6 +5738,7 @@ Examples:
     hermes logs gateway -n 100     Show last 100 lines of gateway.log
     hermes logs --level WARNING    Only show WARNING and above
     hermes logs --session abc123   Filter by session ID
+    hermes logs --component tools  Only show tool-related lines
     hermes logs --since 1h         Lines from the last hour
     hermes logs --since 30m -f     Follow, starting from 30 min ago
     hermes logs list               List available log files with sizes
@@ -5766,6 +5768,10 @@ Examples:
         "--since", metavar="TIME",
         help="Show lines since TIME ago (e.g. 1h, 30m, 2d)",
     )
+    logs_parser.add_argument(
+        "--component", metavar="NAME",
+        help="Filter by component: gateway, agent, tools, cli, cron",
+    )
     logs_parser.set_defaults(func=cmd_logs)
 
     # =========================================================================