fix: gitignore bot/merge junk artifacts (*.orig/*.rej/*.patch/*.diff/*.cover/*.bak) (#690)

Co-authored-by: n24q02m <n24q02m@outlook.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: 3 people

.gitignore

@@ -64,3 +64,11 @@ docs/superpowers/
 coverage.xml
 htmlcov/
 .coverage
+
+# Bot/merge junk artifacts (prevent accidental commits) — 2026-06-07
+*.orig
+*.rej
+*.cover
+*.bak
+/*.patch
+/*.diff