fix(skills): factor HERMES_HOME resolution into shared _hermes_home helper

The three google-workspace scripts (setup.py, google_api.py, gws_bridge.py)
each had their own way of resolving HERMES_HOME:

- setup.py imported hermes_constants (crashes outside Hermes process)
- google_api.py used os.getenv inline (no strip, no empty handling)
- gws_bridge.py defined its own local get_hermes_home() (duplicate)

Extract the common logic into _hermes_home.py which:
- Delegates to hermes_constants when available (profile support, etc.)
- Falls back to os.getenv with .strip() + empty-as-unset handling
- Provides display_hermes_home() with ~/ shortening for profiles

All three scripts now import from _hermes_home instead of duplicating.

7 regression tests cover the fallback path: env var override, default
~/.hermes, empty env var, display shortening, profile paths, and
custom non-home paths.

Closes #12722

skills/productivity/google-workspace/scripts/setup.py

@@ -28,13 +28,12 @@ import subprocess
 import sys
 from pathlib import Path
 
-try:
-    from hermes_constants import display_hermes_home, get_hermes_home
-except ModuleNotFoundError:
-    HERMES_AGENT_ROOT = Path(__file__).resolve().parents[4]
-    if HERMES_AGENT_ROOT.exists():
-        sys.path.insert(0, str(HERMES_AGENT_ROOT))
-    from hermes_constants import display_hermes_home, get_hermes_home
+# Ensure sibling modules (_hermes_home) are importable when run standalone.
+_SCRIPTS_DIR = str(Path(__file__).resolve().parent)
+if _SCRIPTS_DIR not in sys.path:
+    sys.path.insert(0, _SCRIPTS_DIR)
+
+from _hermes_home import display_hermes_home, get_hermes_home
 
 HERMES_HOME = get_hermes_home()
 TOKEN_PATH = HERMES_HOME / "google_token.json"