fix(spaces): add app_port: 8000 to env Space YAML

HF Spaces health-checks port 7860 by default. The env server runs on
8000, so the Space was stuck in "Starting" even though uvicorn was up.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

push_to_hf.sh

@@ -45,6 +45,7 @@ emoji: 🔍
 colorFrom: blue
 colorTo: green
 sdk: docker
+app_port: 8000
 pinned: false
 ---"