Restore to commit 0280ca577f097d7e64a3c6679c5f592feb6ba938

Restore to commit b915c23c (force reset main branch)

Upload ai_runtime_final.py

Apply shorts feature from commit 32da1baa - /api/shorts + /api/ai/short endpoints

Fix: remove incomplete ai_wall_share endpoint, add proper FINAL_INJECT

Squash main