fix: make join approval atomic

harness/tht/cli/decision_cmd.py

@@ -1,7 +1,10 @@
+import json
+import sys
 from pathlib import Path
 from typing import get_args
 
 import typer
+from pydantic import ValidationError
 
 from tht.cli.config_cmd import CONFIG_OPT
 from tht.cli.schema_cmd import _load_config_or_exit
@@ -10,6 +13,40 @@ from tht.cli.session_cmd import load_session_or_exit, session_dir
 decision_app = typer.Typer(help="Decisioni del reviewer (per sessione, append-only)")
 
 
+@decision_app.command("add-join-set")
+def add_join_set_cmd(
+    session: str = typer.Option(..., "--session", help="Id della sessione."),
+    doc: str = typer.Option(..., "--doc", help="Array JSON di join; usa '-' per stdin."),
+    config: Path = CONFIG_OPT,
+) -> None:
+    """Registra un insieme completo di join con un'unica sostituzione atomica del ledger."""
+    from tht.decisions import DecisionInput, append_decisions
+
+    cfg = _load_config_or_exit(config)
+    load_session_or_exit(cfg, session)
+    try:
+        raw = sys.stdin.read() if doc == "-" else Path(doc).read_text()
+        payload = json.loads(raw)
+        if not isinstance(payload, list) or not payload:
+            raise ValueError("il documento deve essere un array JSON non vuoto")
+        decisions = [DecisionInput.model_validate(item) for item in payload]
+        if any(decision.type != "join_modified" for decision in decisions):
+            raise ValueError("tutte le decisioni devono avere type=join_modified")
+    except (OSError, json.JSONDecodeError, ValidationError, ValueError) as error:
+        typer.secho(f"ERRORE: set di join non valido: {error}", fg=typer.colors.RED, err=True)
+        raise typer.Exit(code=1) from error
+
+    from tht.cli.phase_cmd import require_phase_or_exit
+    from tht.workflow import load_workflow
+
+    require_phase_or_exit(cfg, session, load_workflow().decision_min_phase("join_modified"))
+    records = append_decisions(session_dir(cfg, session), decisions)
+    typer.secho(
+        f"OK: registrato set atomico di {len(records)} join.",
+        fg=typer.colors.GREEN,
+    )
+
+
 @decision_app.command("add")
 def add_cmd(
     session: str = typer.Option(..., "--session", help="Id della sessione."),