feat(backend): enforce user-owned sessions

harness/tht/cli/session_cmd.py

@@ -9,6 +9,9 @@ from tht.cli.schema_cmd import _load_config_or_exit
 
 session_app = typer.Typer(help="Sessioni (directory artefatti)")
 
+preferences_app = typer.Typer(help="Preferenze private del principal corrente")
+session_app.add_typer(preferences_app, name="preferences")
+
 
 def session_repository(cfg):
     """Configured persistence boundary for every workflow command."""
@@ -17,6 +20,42 @@ def session_repository(cfg):
     return build_session_repository(cfg)
 
 
+@preferences_app.command("get")
+def preferences_get_cmd(
+    json_out: bool = typer.Option(False, "--json", help="Emetti JSON puro."),
+    config: Path = CONFIG_OPT,
+) -> None:
+    """Legge le preferenze private del principal risolto dal repository."""
+    cfg = _load_config_or_exit(config)
+    preferences = session_repository(cfg).get_preferences()
+    if json_out:
+        typer.echo(json.dumps(preferences, ensure_ascii=False, sort_keys=True))
+    else:
+        typer.echo(json.dumps(preferences, ensure_ascii=False, indent=2, sort_keys=True))
+
+
+@preferences_app.command("set")
+def preferences_set_cmd(
+    preferences_json: str = typer.Argument(..., help="Oggetto JSON delle preferenze."),
+    json_out: bool = typer.Option(False, "--json", help="Non emette testo al successo."),
+    config: Path = CONFIG_OPT,
+) -> None:
+    """Sostituisce le preferenze private del principal risolto dal repository."""
+    try:
+        preferences = json.loads(preferences_json)
+    except json.JSONDecodeError as exc:
+        typer.secho(f"ERRORE: preferenze JSON non valide: {exc}", fg=typer.colors.RED, err=True)
+        raise typer.Exit(code=2) from None
+    if not isinstance(preferences, dict):
+        typer.secho("ERRORE: le preferenze devono essere un oggetto JSON", fg=typer.colors.RED, err=True)
+        raise typer.Exit(code=2)
+    cfg = _load_config_or_exit(config)
+    session_repository(cfg).set_preferences(preferences)
+    if json_out:
+        return
+    typer.secho("OK: preferenze aggiornate.", fg=typer.colors.GREEN)
+
+
 def session_dir(cfg, session_id: str) -> Path:
     """Legacy path bridge for out-of-scope datamart/memory compatibility only.