perf(canvas): 画布媒体 - 优化媒体加载、播放器与节点交互 (#357)

Merge origin/main at fb089b2 and retain canvas media performance, player layout, and interaction updates.

Co-authored-by: ddCat <2695092045@qq.com>

web/src/lib/canvas/canvas-node-stack-order.ts

@@ -0,0 +1,25 @@
+export type CanvasNodeStackOrder = string[];
+
+/**
+ * Keeps the most recently interacted node at the end of the paint order.
+ * This is session-local UI state and is intentionally not persisted with the
+ * canvas document.
+ */
+export function bringCanvasNodeToFront(order: CanvasNodeStackOrder, nodeId: string): CanvasNodeStackOrder {
+    if (!nodeId) return order;
+    if (order.at(-1) === nodeId) return order;
+    return [...order.filter((id) => id !== nodeId), nodeId];
+}
+
+/**
+ * Applies the interaction order while preserving the relative order of nodes
+ * that have not been interacted with yet.
+ */
+export function sortCanvasNodesByStackOrder<T extends { id: string }>(nodes: T[], order: CanvasNodeStackOrder): T[] {
+    if (nodes.length < 2 || order.length === 0) return nodes;
+    const rankById = new Map(order.map((id, index) => [id, index]));
+    return nodes
+        .map((node, index) => ({ node, index, rank: rankById.get(node.id) ?? -1 }))
+        .sort((left, right) => left.rank - right.rank || left.index - right.index)
+        .map(({ node }) => node);
+}