clean-house: fix 37 stale DQR cross-links; sort architecture.md decisions

clean-house sweep over governance/ (validate green, 0 broken refs before
and after):

- RULE-ANCHOR-DRIFT (37): rewrote inline cross-reference links left over
  from before the decisions/questions/rejected subdir split — flat naming
  (questions-architecture.md, questions-process.md, rejected.md) and bare
  same-dir paths that were actually cross-type — to canonical
  subdir-relative form with current slugs. pql resolved these by ID so they
  were never broken to the tooling, only to GitHub anchor navigation.
- RULE-RECORD-SORT (1): reordered decisions/architecture.md D-records to
  strictly ascending (the D-1..D-6 block had been appended after D-41); pure
  block move, line count unchanged, content identical.
- RULE-FILE-OVER-THRESHOLD: deferred (architecture.md 435 > 350; splitting
  would re-churn the anchors just fixed).
- EOF/whitespace and Q↔D backlinks clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -1,6 +1,9 @@
 # -- macOS sandbox (machine-specific paths; template is committed) ------
 /macos/Runner/DebugProfile.entitlements
 
+# -- clean-house skill run history / skip ledger (machine-local) --------
+/governance/decisions/.clean-house-state.md
+
 # -- Flutter / Dart (single package at repo root) -----------------------
 /.dart_tool/
 /.packages