fix(.gitignore): anchor Python build artifacts; recover panel/src/lib (28 files)

The 'lib/' rule (intended for Python virtualenv at repo root) was matching panel/src/lib/, hiding the entire panel API client + utility tree from git. Anchored Python build-artifact rules to the repo root with a leading slash so they only match at the top level. Adds 28 panel/src/lib files that should have been tracked from day one.

.gitignore

@@ -8,24 +8,25 @@
 # Superpowers (session-private design + plans)
 docs/superpowers/
 
-# Python
+# Python (anchored to repo root so the names don't shadow legitimate
+# subdirectories like panel/src/lib).
 __pycache__/
 *.py[cod]
 *$py.class
 *.so
-.Python
-build/
-develop-eggs/
-dist/
-downloads/
-eggs/
-.eggs/
-lib/
-lib64/
-parts/
-sdist/
-var/
-wheels/
+/.Python
+/build/
+/develop-eggs/
+/dist/
+/downloads/
+/eggs/
+/.eggs/
+/lib/
+/lib64/
+/parts/
+/sdist/
+/var/
+/wheels/
 *.egg-info/
 .installed.cfg
 *.egg