Add post-build job to Read the Docs configuration for animated thumbnails

- Updated .readthedocs.yaml to run docs/post_build.py after documentation build
- This ensures animated GIF thumbnails are properly processed on Read the Docs
- Fixes issue where GIFs were not displaying in the online gallery
- All source GIF files are confirmed to be in version control

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: jeremymanning

.readthedocs.yaml

@@ -11,6 +11,10 @@ build:
   tools:
     python: "3.9"
     # You can also specify other tools here or in a separate tools block
+  jobs:
+    post_build:
+      # Fix animated GIF thumbnails after documentation build
+      - python docs/post_build.py
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx: