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/overlays/drawer/DrawerRootNested.vue

@@ -0,0 +1,54 @@
+<script lang="ts">
+/**
+ * A drawer nested inside another drawer. Behaves like DrawerRoot but reports its
+ * drag/open state to the parent so the parent visibly recedes as this one opens.
+ * Place it inside a parent DrawerRoot's content.
+ */
+</script>
+
+<script setup lang="ts">
+import DrawerRoot from './DrawerRoot.vue';
+import type { DrawerRootEmits, DrawerRootProps } from './controls';
+import { injectDrawerRootContext } from './context';
+
+const props = defineProps<DrawerRootProps>();
+const emit = defineEmits<DrawerRootEmits>();
+
+const { onNestedDrag, onNestedOpenChange, onNestedRelease } = injectDrawerRootContext();
+
+function onClose() {
+  onNestedOpenChange(false);
+  emit('close');
+}
+
+function onDrag(percentageDragged: number) {
+  onNestedDrag(percentageDragged);
+  emit('drag', percentageDragged);
+}
+
+function onRelease(open: boolean) {
+  onNestedRelease(open);
+  emit('release', open);
+}
+
+function onOpenChange(open: boolean) {
+  if (open)
+    onNestedOpenChange(open);
+  emit('update:open', open);
+}
+</script>
+
+<template>
+  <DrawerRoot
+    v-bind="props"
+    nested
+    @close="onClose"
+    @drag="onDrag"
+    @release="onRelease"
+    @update:open="onOpenChange"
+    @update:active-snap-point="emit('update:activeSnapPoint', $event)"
+    @animation-end="emit('animationEnd', $event)"
+  >
+    <slot />
+  </DrawerRoot>
+</template>