Refactor messages.ts by removing class-transformer and JS classes (#3858)

* Fix gamma correction with HTML-based editable Text tool text

* Migrate simple, undecorated classes to types

* Remove TupleToVec2 transformation

* Remove @Transform from tooltips

* Cleanup: replace value.toString() with String(value) everywhere

* Convert documentId from string to bigint

* Migrate the rest of the easy @Transform/@Type decorations

* Migrate FillChoice

* Migrate WidgetDiffUpdate

* Migrate WidgetInstance

* Migrate away from classes that extend WidgetProps

* Remove class-transformer and all classes in messages.ts

* Migrate UI layout passing

* Remove dead code

* Remove unnecessary export and readonly prefixes

* Remove HSVA type

* Break out Color, Gradient, and FillChoice functions into a utility-functions file

* Move widget helper functions from messages.ts into a new utility-functions file; restructure type imports

* Reduce internal type defs

* Rename JsMessage to FrontendMessage

* Code review fixes

* Fix other usages

* Tidying up

frontend/eslint.config.js

@@ -87,6 +87,7 @@ export default defineConfig([
 			"svelte/require-each-key": "off", // TODO: Remove this rule and fix the places where it's violated
 
 			// Import plugin config (for intelligently validating module import statements)
+			"import/consistent-type-specifier-style": ["error", "prefer-top-level"],
 			"import/no-unresolved": "error",
 			// `no-duplicates` disabled due to <https://github.com/import-js/eslint-plugin-import/issues/1479#issuecomment-1789527447>. Reenable if that issue gets fixed.
 			"import/no-duplicates": "off",