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/selection/select/SelectPortal.vue

@@ -0,0 +1,21 @@
+<script lang="ts">
+import type { PortalProps } from '../../utilities/teleport';
+
+/**
+ * Teleports the `SelectContent` into a different part of the DOM (the document
+ * body by default) so it escapes overflow and stacking-context clipping.
+ */
+export interface SelectPortalProps extends PortalProps {}
+</script>
+
+<script setup lang="ts">
+import { Portal } from '../../utilities/teleport';
+
+const { to, defer, disabled } = defineProps<SelectPortalProps>();
+</script>
+
+<template>
+  <Portal :to="to" :defer="defer" :disabled="disabled">
+    <slot />
+  </Portal>
+</template>