feat(primitives): media-editor components, category reorg, perf + type cleanup

Reorganize components into category folders (forms/canvas/overlays/etc.); add the
media-editor headless family (timeline, curve-editor, waveform, crop, color
picker, etc.); apply perf fixes (O(1) collection lookups, plain-object drag
state, gesture-leak teardown, shallowRef color state, rect caching) and replace
source `any` with proper types.

vue/primitives/tsdown.config.ts

@@ -5,7 +5,8 @@ import Vue from 'unplugin-vue/rolldown';
 export default defineConfig({
   ...sharedConfig,
   tsconfig: './tsconfig.src.json',
-  entry: ['src/index.ts', 'src/*/index.ts'],
+  // Components live one level deep now: src/<category>/<component>/index.ts.
+  entry: ['src/index.ts', 'src/*/*/index.ts'],
   plugins: [Vue({ isProduction: true })],
   dts: { vue: true },
   deps: {