feat(harness): add local session repository

harness/tht/config.py

@@ -16,6 +16,11 @@ class ConfigError(Exception):
     """Errore di configurazione, con messaggio leggibile per l'utente."""
 
 
+def local_tht_home() -> Path:
+    """Return the private local ThothII home, honoring the explicit override."""
+    return Path(os.environ.get("THT_HOME", "~/.thothii")).expanduser()
+
+
 def _expand_env(value: Any) -> Any:
     if isinstance(value, str):
 
@@ -356,7 +361,9 @@ def load_config(path: Path) -> Config:
         raise ConfigError(
             f"transport: rest richiede la sezione `rest` (base_url, api_key) in {path}."
         )
-    data_root = os.environ.get("THT_DATA_ROOT")
+    # THT_HOME is the local-user storage root.  Retain THT_DATA_ROOT as the
+    # portable-deployment compatibility name until all callers use repositories.
+    data_root = os.environ.get("THT_HOME") or os.environ.get("THT_DATA_ROOT")
     if data_root:
         # Import locally: paths owns resolution, while ConfigError remains the public
         # configuration exception callers already handle.