simpleshot: pyproject to the registry's spec, and keep tests out of the archive

license points at the LICENSE file rather than naming the licence inline — both
forms are legal per the spec, the file reference cannot disagree with the file.

.comfyignore drops tests/ from the published archive. They stay in git because
they are the evidence this pack works; nobody installing it needs them in their
custom_nodes folder.

.comfyignore

@@ -0,0 +1,3 @@
+# Kept in git because they are the evidence this pack works, but a user
+# installing it does not need them in their custom_nodes folder.
+tests/

pyproject.toml

@@ -2,7 +2,7 @@
 name = "comfyui-simpleshot"
 description = "MiniMax-H3 video with sound in one node: prompt, an optional first and last frame, and nothing that can be set wrongly. Core-only, no second pack to install."
 version = "1.0.0"
-license = { text = "MIT" }
+license = { file = "LICENSE" }
 requires-python = ">=3.10"
 dependencies = []
 
@@ -12,4 +12,4 @@ Repository = "https://github.com/manzakin/ComfyUI-SimpleShot"
 [tool.comfy]
 PublisherId = "manzakin"
 DisplayName = "SimpleShot"
-Icon = ""
+Icon = ""   # optional: PNG/SVG/JPG/GIF, max 800x400