chore: stop tracking controller-query scratch files (.sta.json); gitignore temp patterns

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

.gitignore

@@ -112,3 +112,15 @@ temp/
 .claude/wiki_staging/*
 !.claude/wiki_staging/README.md
 .tmp-*
+
+# Controller/API scratch files (transient session temp; never commit)
+.sta.json
+.dev.json
+.nc.json
+.nc2.json
+.cj_tmp
+.q*
+.po_*.json
+.put*.json
+.hdr
+.csrf_tmp