fix: bundle og-image.png in API container

The og-image.png was in app/public/ which only exists in the frontend
container. Move to api/static/ so it's bundled in the API Docker image.

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: MarkusNeusinger

api/routers/og_images.py

@@ -23,7 +23,8 @@ def _get_static_og_image() -> bytes:
     """Load static og-image.png (cached in memory)."""
     global _STATIC_OG_IMAGE
     if _STATIC_OG_IMAGE is None:
-        path = Path(__file__).parent.parent.parent / "app" / "public" / "og-image.png"
+        # Use api/static/ which is bundled in the Docker image
+        path = Path(__file__).parent.parent / "static" / "og-image.png"
         try:
             _STATIC_OG_IMAGE = path.read_bytes()
         except FileNotFoundError as exc: