feat: centralized logging, instrumentation, hermes logs CLI, gateway noise fix (#5430)

Adds comprehensive logging infrastructure to Hermes Agent across 4 phases:

**Phase 1 — Centralized logging**
- New hermes_logging.py with idempotent setup_logging() used by CLI, gateway, and cron
- agent.log (INFO+) and errors.log (WARNING+) with RotatingFileHandler + RedactingFormatter
- config.yaml logging: section (level, max_size_mb, backup_count)
- All entry points wired (cli.py, main.py, gateway/run.py, run_agent.py)
- Fixed debug_helpers.py writing to ./logs/ instead of ~/.hermes/logs/

**Phase 2 — Event instrumentation**
- API calls: model, provider, tokens, latency, cache hit %
- Tool execution: name, duration, result size (both sequential + concurrent)
- Session lifecycle: turn start (session/model/provider/platform), compression (before/after)
- Credential pool: rotation events, exhaustion tracking

**Phase 3 — hermes logs CLI command**
- hermes logs / hermes logs -f / hermes logs errors / hermes logs gateway
- --level, --session, --since filters
- hermes logs list (file sizes + ages)

**Phase 4 — Gateway bug fix + noise reduction**
- fix: _async_flush_memories() called with wrong arg count — sessions never flushed
- Batched session expiry logs: 6 lines/cycle → 2 summary lines
- Added inbound message + response time logging

75 new tests, zero regressions on the full suite.

cli.py

@@ -453,6 +453,14 @@ def load_cli_config() -> Dict[str, Any]:
 # Load configuration at module startup
 CLI_CONFIG = load_cli_config()
 
+# Initialize centralized logging early — agent.log + errors.log in ~/.hermes/logs/.
+# This ensures CLI sessions produce a log trail even before AIAgent is instantiated.
+try:
+    from hermes_logging import setup_logging
+    setup_logging(mode="cli")
+except Exception:
+    pass  # Logging setup is best-effort — don't crash the CLI
+
 # Validate config structure early — print warnings before user hits cryptic errors
 try:
     from hermes_cli.config import print_config_warnings