Relax Python requirement to >=3.10 for HF Spaces compatibility

HF ZeroGPU spaces run Python 3.10; the >=3.13 constraint caused uv to
skip dependency installation entirely, leaving diffusers and other
packages missing at runtime.

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

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "firered-image-edit"
 version = "1.0.0"
-requires-python = ">=3.13"
+requires-python = ">=3.10"
 dependencies = [
     "transformers>=5.0.0",
     "huggingface_hub",