fix(v0.6.4): rollback removes the proposal's ab-tracking entry

adam-rollback.mjs's docstring always claimed it "removes the ab-tracking entry
(so it doesn't re-trigger)", but executeRollback() never did. Consequence: a
rolled-back proposal kept being re-detected as `regressed` on every subsequent
/reflect, which triggered endless `not_found` rollback attempts (the applied
file is already gone) and noisy ## Regressions sections.

executeRollback now deletes the matching ab-tracking.jsonl row by proposal_id
after the move, preserving all unrelated rows. Surfaced by running ADAM's own
/reflect loop a second time (two zombie regressions: 2026-05-16-002 and
2026-05-22-001).

Tests: 138 -> 140 (rollback purges the entry by id; an unrelated entry is
preserved).

adam/tests/run-tests.sh

@@ -2109,6 +2109,45 @@ else
 fi
 rm -f "$ROOT/.update-check.json"
 
+# --- Test 118: rollback removes the proposal's ab-tracking entry (stops re-flagging) ---
+echo "Test 118: rollback purges ab-tracking entry by proposal_id"
+reset_state
+rm -f "$ROOT/proposals/"*rollback* "$ROOT/active-nudges.json"
+cat > "$ROOT/applied/2026-05-20T00-00-00Z-rb-ab-001.md" <<'EOF'
+---
+id: rb-ab-001
+type: memory
+target: ~/.claude/projects/-Users-nvm/memory/x.md
+confidence: 5
+blast_radius: low
+status: applied
+source_entries:
+  - "2026-05-18T10:00:00Z"
+---
+# Why
+test
+# Rollback
+```bash
+rm -f x
+```
+EOF
+cat > "$ROOT/ab-tracking.jsonl" <<'EOF'
+{"applied_at":1,"proposal_id":"rb-ab-001","proposal_type":"memory","target_skill":"x","proposal_fingerprint":"f1","originating_signals":[{"type":"correction","count":3}],"pre_window_days":7}
+{"applied_at":2,"proposal_id":"keep-me-002","proposal_type":"memory","target_skill":"y","proposal_fingerprint":"f2","originating_signals":[{"type":"correction","count":3}],"pre_window_days":7}
+EOF
+ROLLBACK_RUN --proposal-id rb-ab-001 --home "$TMP_HOME/.claude" >/dev/null 2>&1 || true
+if grep -q '"proposal_id":"rb-ab-001"' "$ROOT/ab-tracking.jsonl"; then
+  echo "  FAIL: rolled-back proposal still in ab-tracking.jsonl"; FAIL=$((FAIL+1))
+else
+  echo "  PASS: rolled-back proposal removed from ab-tracking.jsonl"; PASS=$((PASS+1))
+fi
+if grep -q '"proposal_id":"keep-me-002"' "$ROOT/ab-tracking.jsonl"; then
+  echo "  PASS: unrelated ab-tracking entry preserved"; PASS=$((PASS+1))
+else
+  echo "  FAIL: rollback clobbered an unrelated ab-tracking entry"; FAIL=$((FAIL+1))
+fi
+rm -f "$ROOT/proposals/"*rb-ab-001* "$ROOT/applied/"*rb-ab-001* "$ROOT/ab-tracking.jsonl" "$ROOT/active-nudges.json"
+
 echo
 echo "Results: $PASS passed, $FAIL failed"
 [ "$FAIL" = "0" ]