Guard _install_cuda_packages() startup call against quota exhaustion

If ZeroGPU quota is exhausted at startup, the @spaces.GPU decorator
throws — previously this crashed module import causing RUNTIME_ERROR.
Now wrapped in try/except so the app stays alive; CUDA extensions will
be unavailable but each GPU-decorated function handles that gracefully.

app.py

@@ -210,7 +210,12 @@ def _install_cuda_packages():
     _CUDA_PKG_MARKER.touch()
     print("[startup] CUDA packages installed.")
 
-_install_cuda_packages()
+try:
+    _install_cuda_packages()
+except Exception as _e:
+    # Quota exhaustion or GPU unavailable at startup — CUDA extensions may be missing,
+    # but don't crash the app. Each GPU-decorated function will handle missing imports.
+    print(f"[startup] WARNING: _install_cuda_packages failed ({type(_e).__name__}): {_e}")
 # ── Paths ─────────────────────────────────────────────────────────────────────
 HERE        = Path(__file__).parent
 PIPELINE_DIR = HERE / "pipeline"