refactor: consolidate get_hermes_home() and parse_reasoning_effort() (#3062)

Centralizes two widely-duplicated patterns into hermes_constants.py:

1. get_hermes_home() — Path resolution for ~/.hermes (HERMES_HOME env var)
   - Was copy-pasted inline across 30+ files as:
     Path(os.getenv("HERMES_HOME", Path.home() / ".hermes"))
   - Now defined once in hermes_constants.py (zero-dependency module)
   - hermes_cli/config.py re-exports it for backward compatibility
   - Removed local wrapper functions in honcho_integration/client.py,
     tools/website_policy.py, tools/tirith_security.py, hermes_cli/uninstall.py

2. parse_reasoning_effort() — Reasoning effort string validation
   - Was copy-pasted in cli.py, gateway/run.py, cron/scheduler.py
   - Same validation logic: check against (xhigh, high, medium, low, minimal, none)
   - Now defined once in hermes_constants.py, called from all 3 locations
   - Warning log for unknown values kept at call sites (context-specific)

31 files changed, net +31 lines (125 insertions, 94 deletions)
Full test suite: 6179 passed, 0 failed

hermes_cli/skin_engine.py

@@ -101,6 +101,8 @@ from dataclasses import dataclass, field
 from pathlib import Path
 from typing import Any, Dict, List, Optional, Tuple
 
+from hermes_constants import get_hermes_home
+
 logger = logging.getLogger(__name__)
 
 
@@ -513,8 +515,7 @@ _active_skin_name: str = "default"
 
 def _skins_dir() -> Path:
     """User skins directory."""
-    home = Path(os.getenv("HERMES_HOME", Path.home() / ".hermes"))
-    return home / "skins"
+    return get_hermes_home() / "skins"
 
 
 def _load_skin_from_yaml(path: Path) -> Optional[Dict[str, Any]]: