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/src/menus/dropdown-menu/DropdownMenuPortal.vue

@@ -0,0 +1,19 @@
+<script lang="ts">
+import type { MenuPortalProps } from '../menu';
+
+/**
+ * Teleports the menu content into the document body (or a chosen target) so it
+ * renders above other content and escapes any `overflow: hidden` ancestor.
+ */
+export interface DropdownMenuPortalProps extends MenuPortalProps {}
+</script>
+
+<script setup lang="ts">
+import { MenuPortal } from '../menu';
+
+const props = defineProps<DropdownMenuPortalProps>();
+</script>
+
+<template>
+  <MenuPortal v-bind="props"><slot /></MenuPortal>
+</template>