chore: auto-commit (5 archivos)

- CMakeLists.txt
- app.md
- appicon.ico
- backend/
- main.cpp

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/backends/_iface.py

@@ -0,0 +1,17 @@
+"""Interfaz comun para backends image-to-3D.
+
+Cada backend (triposr, hunyuan3d_2, trellis) expone:
+  load() -> Handle
+  donde Handle tiene metodo infer(image: PIL.Image, cfg: dict) -> bytes (GLB).
+
+`cfg` recibe: seed, mc_resolution, foreground_ratio, texture.
+"""
+from __future__ import annotations
+
+from typing import Protocol, Any, Dict
+from PIL import Image
+
+
+class BackendHandle(Protocol):
+    def infer(self, image: Image.Image, cfg: Dict[str, Any]) -> bytes: ...
+    def close(self) -> None: ...