Phase 2: persistence + safety controls

Aggiunge la persistenza SQLite, l'audit log a hash chain, il kill
switch coordinato e i CLI di gestione documentati in
docs/05-data-model.md e docs/07-risk-controls.md. 197 test pass,
1 skipped (sqlite3 CLI mancante), copertura totale 97%.

State (`state/`):
- 0001_init.sql con positions, instructions, decisions, dvol_history,
  manual_actions, system_state.
- db.py: connect con WAL + foreign_keys + transaction ctx, runner
  forward-only basato su PRAGMA user_version.
- models.py: record Pydantic, Decimal preservato come TEXT.
- repository.py: CRUD typed con singola connessione passata, cache
  aware, posizioni concorrenti.

Safety (`safety/`):
- audit_log.py: AuditLog append-only con SHA-256 chain e fsync,
  verify_chain riconosce ogni manomissione (payload, prev_hash,
  hash, JSON, separatori).
- kill_switch.py: arm/disarm transazionali, idempotenti, accoppiati
  all'audit chain.

Config (`config/loader.py` + `strategy.yaml`):
- Loader YAML con deep-merge di strategy.local.yaml.
- Verifica config_hash SHA-256 (riga config_hash esclusa).
- File golden strategy.yaml + esempio override.

Scripts:
- dead_man.sh: watchdog shell indipendente da Python.
- backup.py: VACUUM INTO orario con retention 30 giorni.

CLI:
- audit verify (exit 2 su tampering).
- kill-switch arm/disarm/status su SQLite reale.
- state inspect con tabella posizioni aperte.
- config hash, config validate.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/unit/test_smoke.py

@@ -38,14 +38,29 @@ def test_cli_status_runs(tmp_data_dir: Path) -> None:
     assert "phase: 0" in result.output
 
 
-def test_cli_kill_switch_arm_placeholder(tmp_data_dir: Path) -> None:
+def test_cli_kill_switch_arm_persists_state(tmp_data_dir: Path) -> None:
     runner = CliRunner()
+    db_path = tmp_data_dir / "state.sqlite"
+    audit_path = tmp_data_dir / "audit.log"
     result = runner.invoke(
         cli_main,
-        ["--log-dir", str(tmp_data_dir / "log"), "kill-switch", "arm", "--reason", "test"],
+        [
+            "--log-dir",
+            str(tmp_data_dir / "log"),
+            "kill-switch",
+            "arm",
+            "--reason",
+            "smoke",
+            "--db",
+            str(db_path),
+            "--audit",
+            str(audit_path),
+        ],
     )
-    assert result.exit_code == 0
-    assert "phase 0 placeholder" in result.output
+    assert result.exit_code == 0, result.output
+    assert "ARMED" in result.output
+    assert db_path.exists()
+    assert audit_path.exists()
 
 
 def test_cli_version_flag() -> None: