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.

tools/debug_helpers.py

@@ -29,6 +29,8 @@ import uuid
 from pathlib import Path
 from typing import Any, Dict
 
+from hermes_constants import get_hermes_home
+
 logger = logging.getLogger(__name__)
 
 
@@ -43,12 +45,12 @@ class DebugSession:
         self.tool_name = tool_name
         self.enabled = os.getenv(env_var, "false").lower() == "true"
         self.session_id = str(uuid.uuid4()) if self.enabled else ""
-        self.log_dir = Path("./logs")
+        self.log_dir = get_hermes_home() / "logs"
         self._calls: list[Dict[str, Any]] = []
         self._start_time = datetime.datetime.now().isoformat() if self.enabled else ""
 
         if self.enabled:
-            self.log_dir.mkdir(exist_ok=True)
+            self.log_dir.mkdir(parents=True, exist_ok=True)
             logger.debug("%s debug mode enabled - Session ID: %s",
                          tool_name, self.session_id)