ci: harden contributor checks (#254)

* ci: harden contributor checks

* ci: pin setup-uv action release

* ci: split workflow checks

* docs: clarify required checks

.gitignore

@@ -50,6 +50,10 @@ coverage.xml
 *.py,cover
 .hypothesis/
 .pytest_cache/
+.ruff_cache/
+.import_linter_cache/
+.uv-cache/
+.package-smoke/
 
 # Translations
 *.mo
@@ -146,6 +150,8 @@ dmypy.json
 !.claude/settings.json
 .claude/settings.local.json
 .claude/worktrees/
+.worktrees/
+worktrees/
 
 # Runtime data (the default memory root + local databases)
 .everos/