chore: add .mypy_cache and .venv to gitignore

.gitignore

@@ -8,6 +8,10 @@ skills-lock.json
 
 # python cache
 __pycache__/
+.mypy_cache/
+
+# python virtual environment
+.venv/
 
 # app runtime data (feeds, caches, scan state - regenerated each run)
 app/data/