Add Tilesmith to Plugins and scripts (Godot 4)

[DJsluxx]

Adds Tilesmith, an editor addon that batch-builds a Godot 4 TileSet from a folder of images: it skips blank cells and bakes convex collision shapes, so you don't hand-draw a collision polygon per tile.

• Licence: MIT, at the repository root.
• Compatibility: Godot 4, built and tested on 4.7.1. Listed under Godot 4.
• Placed alphabetically between ThemeGen and UI Design Tool.
• Pure GDScript, no native code or external dependencies.
• Test suite runs headless: godot --headless --path . --script res://tests/run_tests.gd (89 assertions).

Disclosure: I am the author. There is a paid edition; everything in the linked repository is MIT and fully functional on its own.