chore: ignore the tooling-generated AGENTS.md / .agents mirrors

Both are copies of files already in the untracked .claude/ directory --
AGENTS.md of .claude/CLAUDE.md, .agents/skills/ of .claude/skills/ --
written by the agent tooling, not by hand. They were never tracked, and
a `git add -A` sweeping them into an unrelated commit is exactly what
this prevents.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.gitignore

@@ -100,6 +100,9 @@ Thumbs.db
 # Miscellaneous
 # ============================================
 .claude/
+# Tooling-generated mirrors of .claude/CLAUDE.md and .claude/skills/
+AGENTS.md
+.agents/
 technotes/
 docs/Pomoc w zwiększeniu zasięgu.pdf
 PRD.md