chore: untrack CLAUDE.md, gitignore AI-tool instruction files

Project-level AI-tool instruction files (CLAUDE.md, AGENTS.md,
GEMINI.md, .cursorrules, .windsurfrules, .aider.conf.yml) are
operator-scoped working notes, not project artifacts. Other
contributors don't need them, and committing them conflates
operator preferences with shared project conventions.

CLAUDE.md remains on the local disk (untracked) so Claude Code
keeps loading it for this checkout; new clones simply won't have
it, which is the desired state.

.gitignore

@@ -38,11 +38,19 @@ go.work.sum
 # canonical record lives in commit messages and the running code).
 docs/superpowers/
 
-# Per-machine Claude Code settings + remember-skill memory artifacts.
-# Both are operator-scoped; the canonical project memory lives under
-# ~/.claude/projects/ outside the repo.
+# Per-machine Claude Code settings + remember-skill memory artifacts +
+# project-level Claude/AI instruction files. All operator-scoped; the
+# canonical project memory lives under ~/.claude/projects/ outside the
+# repo. CLAUDE.md/AGENTS.md/GEMINI.md stay on the operator's machine
+# only — they're tool-specific working notes, not project artifacts.
 .claude/
 .remember/
+CLAUDE.md
+AGENTS.md
+GEMINI.md
+.cursorrules
+.windsurfrules
+.aider.conf.yml
 
 # Flutter
 flutter_client/.dart_tool/