fix: Expand tilde in get_hermes_home() when HERMES_HOME=~/...

Closes #478. Uses Path.expanduser() to expand ~ to user's home directory.

hermes_constants.py

@@ -12,9 +12,14 @@ def get_hermes_home() -> Path:
     """Return the Hermes home directory (default: ~/.hermes).
 
     Reads HERMES_HOME env var, falls back to ~/.hermes.
+    Expands ~ to user's home directory if present.
     This is the single source of truth — all other copies should import this.
     """
-    return Path(os.getenv("HERMES_HOME", Path.home() / ".hermes"))
+    hermes_home = os.getenv("HERMES_HOME")
+    if hermes_home:
+        # Expand ~ to user's home directory
+        return Path(hermes_home).expanduser()
+    return Path.home() / ".hermes"
 
 
 def get_optional_skills_dir(default: Path | None = None) -> Path: