chore(deps): drop <3.13 Python cap, require coreml-diffusion>=0.1.6 (#68)

Mirror the library: coreml-diffusion 0.1.6 dropped its stale <3.13 cap, so this
package can too (requires-python >=3.12). Bump the dependency floor to 0.1.6 to
keep the cap consistent across both — a consumer pinned to <3.13 with a library
allowing 3.13+ would be unresolvable for the 3.13 range. Pin the dev/CI
interpreter to 3.12 via .python-version so CI runs on a fixed baseline rather
than floating to a newer Python without a pinned-torch wheel.

Author: aszc-dev

.python-version

@@ -0,0 +1 @@
+3.12

pyproject.toml

@@ -7,13 +7,14 @@ name = "comfyui-coremlsuite"
 description = "This extension contains a set of custom nodes for ComfyUI that allow you to use Core ML models in your ComfyUI workflows."
 version = "2.1.2"
 license = "MIT"
-requires-python = ">=3.12,<3.13"
+requires-python = ">=3.12"
 dependencies = [
     # torch is provided by the host (ComfyUI) and intentionally left unpinned
     # here: a hard torch cap would downgrade the host's torch and break its
     # torchvision/torchaudio ABI. coreml-diffusion pulls torch>=2.7 transitively.
-    # >=0.1.5: model-version auto-detection (convert(model_version=None)).
-    "coreml-diffusion>=0.1.5,<0.2",
+    # >=0.1.6: model-version auto-detection (convert(model_version=None)) and the
+    # dropped <3.13 Python cap (kept in sync with this package's requires-python).
+    "coreml-diffusion>=0.1.6,<0.2",
     "coremltools>=9,<10",
     "numpy>=2,<3",
 ]