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/utilities/config-provider/useDateAdapter.ts

@@ -0,0 +1,26 @@
+import type { ComputedRef, MaybeRefOrGetter } from 'vue';
+import type { DateAdapter } from './date-adapter';
+import { computed, toValue } from 'vue';
+import { useConfig } from './context';
+
+/**
+ * Resolves the effective {@link DateAdapter}: a per-component override wins over
+ * the active `ConfigProvider` `dateAdapter`, which falls back to the native
+ * `Date` adapter. Lets calendar/date-picker primitives route every date
+ * operation through a single, swappable backend instead of hard-coding `Date`.
+ *
+ * The type parameter `TDate` re-asserts the concrete date representation at the
+ * call site (the context stores a type-erased adapter), so a primitive built on
+ * a custom adapter gets correctly-typed dates back.
+ *
+ * @param override Optional per-component adapter override.
+ * @returns A computed `DateAdapter<TDate>` combining the override with config.
+ */
+export function useDateAdapter<TDate = Date>(
+  override?: MaybeRefOrGetter<DateAdapter<TDate> | undefined>,
+): ComputedRef<DateAdapter<TDate>> {
+  const config = useConfig();
+  return computed(
+    () => (toValue(override) ?? config.dateAdapter.value) as DateAdapter<TDate>,
+  );
+}