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/l2/test_memory_save_one_real.py

@@ -9,7 +9,6 @@ Run: pytest -m l2 tests/l2/test_memory_save_one_real.py -s  (needs .env + VPN +
 """
 from datetime import datetime
 from pathlib import Path
-from unittest.mock import MagicMock
 
 import pytest
 

harness/tests/l2/test_session_ablazione.py

@@ -71,7 +71,7 @@ def test_ablazione_session_manual(l2_env, tmp_path):
                  ["THT_DWH_API_KEY", "THT_VEC_API_KEY", "THT_VEC_WRITE_API_KEY"])
     assert env_ok
     assert WORKSPACE.exists()
-    print(f"\n[L2 manual] launch: pi --mode rpc (cwd=harness/)")
+    print("\n[L2 manual] launch: pi --mode rpc (cwd=harness/)")
     print(f"[L2 manual] /nuova-domanda \"{QUESTION}\"")
     print("[L2 manual] confirm: sql_final.sql present + ledger has value_grounded/"
           "concept_formula_approved. Session dir:", tmp_path)

harness/tests/l2/test_value_grounding_real.py

@@ -25,7 +25,6 @@ def test_ablazione_returns_multiple_columns(l2_env):
     non-collapsing aggregation. Requires a built LSH index (tht lsh build)."""
     if not WORKSPACE.exists():
         pytest.skip(f"per-customer workspace repo not found: {WORKSPACE} (clone tht-workspace-psd)")
-    from tht.config import LshConfig
     try:
         from tht.lshindex import load_index, query_index  # ported with the lsh build path
     except ModuleNotFoundError: