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/canvas/compare-slider/CompareSliderDivider.vue

@@ -0,0 +1,70 @@
+<script lang="ts">
+import type { PrimitiveProps } from '../../internal/primitive';
+
+/**
+ * A thin presentational line marking the split between the before and after
+ * layers, positioned at the current reveal position. It is purely decorative
+ * (no role, no keyboard) — the focusable, screen-reader-accessible target is
+ * `CompareSliderHandle`.
+ *
+ * The recommended two-element pattern is a thin `CompareSliderDivider` line for
+ * the visible seam plus a larger `CompareSliderHandle` "puck" for the grab /
+ * focus target sitting on top of it (give the handle a wider hit-area via CSS).
+ * Render the divider as a sibling or wrapper of the handle inside the root.
+ */
+export interface CompareSliderDividerProps extends PrimitiveProps {}
+</script>
+
+<script setup lang="ts">
+import { Primitive } from '../../internal/primitive';
+import { computed } from 'vue';
+import { useForwardExpose } from '@robonen/vue';
+import { useCompareSliderContext } from './context';
+
+const { as = 'span' } = defineProps<CompareSliderDividerProps>();
+const ctx = useCompareSliderContext();
+const { forwardRef } = useForwardExpose();
+
+// Sit on the divider. Stable shape: same keys in the same order; the `flip` flag
+// selects the positioning edge so the line tracks the after-layer clip side.
+const style = computed<{
+  position: string;
+  left: string | undefined;
+  right: string | undefined;
+  top: string | undefined;
+  bottom: string | undefined;
+}>(() => {
+  const pct = `${ctx.position.value}%`;
+  const horizontal = ctx.orientation.value === 'horizontal';
+  const flip = ctx.flip.value;
+  if (horizontal) {
+    return {
+      position: 'absolute',
+      left: flip ? undefined : pct,
+      right: flip ? pct : undefined,
+      top: undefined,
+      bottom: undefined,
+    };
+  }
+  return {
+    position: 'absolute',
+    left: undefined,
+    right: undefined,
+    top: flip ? undefined : pct,
+    bottom: flip ? pct : undefined,
+  };
+});
+</script>
+
+<template>
+  <Primitive
+    :ref="forwardRef"
+    :as="as"
+    aria-hidden="true"
+    :style="style"
+    :data-disabled="ctx.disabled.value ? '' : undefined"
+    :data-orientation="ctx.orientation.value"
+  >
+    <slot :position="ctx.position.value" />
+  </Primitive>
+</template>