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/DrawerOverlay.vue

@@ -0,0 +1,37 @@
+<script lang="ts">
+import type { DialogOverlayProps } from '../dialog';
+
+/**
+ * The dimming layer behind the drawer. Wraps Dialog's Overlay and exposes the
+ * `data-drawer-overlay` hooks so its opacity can fade in step with the drag and
+ * with snap points. Only renders for modal drawers.
+ */
+export interface DrawerOverlayProps extends DialogOverlayProps {}
+</script>
+
+<script setup lang="ts">
+import { watch } from 'vue';
+import { useForwardExpose } from '@robonen/vue';
+import { DialogOverlay } from '../dialog';
+import { injectDrawerRootContext } from './context';
+
+defineProps<DrawerOverlayProps>();
+
+const { overlayRef, hasSnapPoints, isOpen, shouldFade } = injectDrawerRootContext();
+const { forwardRef, currentElement } = useForwardExpose();
+
+watch(currentElement, (el) => {
+  overlayRef.value = el as HTMLElement | undefined;
+}, { immediate: true, flush: 'post' });
+</script>
+
+<template>
+  <DialogOverlay
+    :ref="forwardRef"
+    data-drawer-overlay
+    :data-drawer-snap-points="isOpen && hasSnapPoints ? 'true' : 'false'"
+    :data-drawer-snap-points-overlay="isOpen && shouldFade ? 'true' : 'false'"
+  >
+    <slot />
+  </DialogOverlay>
+</template>