fix(codex): resolve peer-review findings R1-R6 and T1-T2

- R1: use herdr send-keys C-c for graceful stop
- R2: preserve JSONL fallback discovery when database is empty
- R3: apply workspace-scoped SQLite query before bounding results
- R4: tighten artifact validation to fail closed on missing/invalid metadata
- R5: verify actual rollout presence before reporting resumable in status
- R6: remove unconditional drift-B backend command fallback
- T1: parameterize artifact metadata regression with verified finder fixture
- T2: seed unmanaged and managed sessions in mock herdr for drift-B testing
- Add final loop review reports (100% PASS)

.agents/skills/multi-agent-mux-status/scripts/status.sh

@@ -139,8 +139,6 @@ def resume_on_disk(s):
                     conn.close()
                     if r and r[0] and os.path.exists(r[0]):
                         return 'yes'
-                    if r:
-                        return 'yes'
                 except Exception:
                     pass
             m = glob.glob(f"{codex_home}/sessions/*/*/*/rollout-*-{u}.jsonl")
@@ -340,8 +338,6 @@ def resume_on_disk(s):
                     conn.close()
                     if r and r[0] and os.path.exists(r[0]):
                         return 'yes'
-                    if r:
-                        return 'yes'
                 except Exception:
                     pass
             m = glob.glob(f"{codex_home}/sessions/*/*/*/rollout-*-{u}.jsonl")