chore: hygiene pass — ruff clean, docs storage-model truth, replay /me, failSession log

Audit findings 6.1-6.4 + the audit's remediation plan itself
(docs/superpowers/plans/2026-07-20-full-audit-remediation-plan.md).

- ruff: 34 → 0 (unused imports/f-strings auto-fixed; E702 semicolon lines
  split in test files; one unused local dropped). Suite still 819 green.
- CLAUDE.md + PROJECT_STATE.md no longer claim "no database / settings in
  settings.json": the harness selects filesystem OR PostgreSQL session
  storage (repository.py, server mode), and settings flow through harness
  preferences with the JSON file as fallback only.
- tools/replay: stub /me (SPA boot was parsing the SPA's own HTML as JSON)
  and /runtime/prewarm.
- failSession best-effort persistence now logs its failure server-side
  instead of vanishing.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

harness/tests/test_teardown.py

@@ -2,7 +2,8 @@ from tht.teardown import teardown_to_phase
 
 
 def test_teardown_to_phase_4_deletes_phase5plus_artifacts(tmp_path):
-    s = tmp_path / "sess"; s.mkdir()
+    s = tmp_path / "sess"
+    s.mkdir()
     (s / "schema_linking.json").write_text("{}")    # F4 artifact
     (s / "cte_plan.json").write_text("[]")          # F6 artifact
     (s / "ctes").mkdir()
@@ -19,7 +20,8 @@ def test_teardown_to_phase_4_deletes_phase5plus_artifacts(tmp_path):
 
 def test_teardown_to_phase_1_deletes_everything(tmp_path):
     """Rollback a F1 cancella tutti gli artefatti (tutte le fasi > 1)."""
-    s = tmp_path / "sess"; s.mkdir()
+    s = tmp_path / "sess"
+    s.mkdir()
     (s / "question.md").write_text("q")             # F3 artifact
     (s / "schema_linking.json").write_text("{}")    # F4 artifact
     (s / "cte_plan.json").write_text("[]")          # F6 artifact
@@ -37,7 +39,8 @@ def test_teardown_to_phase_1_deletes_everything(tmp_path):
 
 def test_teardown_to_phase_7_preserves_phase6_artifacts(tmp_path):
     """Rollback a F7 preserva gli artefatti delle fasi <= 7."""
-    s = tmp_path / "sess"; s.mkdir()
+    s = tmp_path / "sess"
+    s.mkdir()
     (s / "schema_linking.json").write_text("{}")    # F4 artifact
     (s / "cte_plan.json").write_text("[]")          # F6 artifact
     (s / "ctes").mkdir()
@@ -52,14 +55,16 @@ def test_teardown_to_phase_7_preserves_phase6_artifacts(tmp_path):
 
 
 def test_teardown_to_phase_on_empty_session_is_noop(tmp_path):
-    s = tmp_path / "sess"; s.mkdir()
+    s = tmp_path / "sess"
+    s.mkdir()
     report = teardown_to_phase(s, target_phase=4)
     assert report.deleted_files == []
 
 
 def test_teardown_to_phase_nonexistent_artifacts_no_error(tmp_path):
     """Se gli artefatti non esistono (sessione nuova), teardown non fallisce."""
-    s = tmp_path / "sess"; s.mkdir()
+    s = tmp_path / "sess"
+    s.mkdir()
     report = teardown_to_phase(s, target_phase=1)
     assert report.deleted_files == []
 
@@ -67,7 +72,8 @@ def test_teardown_to_phase_nonexistent_artifacts_no_error(tmp_path):
 def test_teardown_deletes_orphaned_cte_files_not_in_current_plan(tmp_path):
     """Il bug degli orfani CTE: dopo un re-derive con piano diverso, i vecchi .sql
     non piu' nel piano restano su disco e bloccano finalize. teardown li pulisce."""
-    s = tmp_path / "sess"; s.mkdir()
+    s = tmp_path / "sess"
+    s.mkdir()
     (s / "ctes").mkdir()
     (s / "ctes" / "old_cte.sql").write_text("SELECT 1")   # orphan
     (s / "ctes" / "another.sql").write_text("SELECT 2")   # orphan