feat: improve grouping perf in edgeless (#14442)

fix #14433 

#### PR Dependency Tree


* **PR #14442** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
  * Level-of-detail thumbnails for large images.
  * Adaptive pacing for snapping, distribution and other alignment work.
  * RAF coalescer utility to batch high-frequency updates.
  * Operation timing utility to measure synchronous work.

* **Improvements**
* Batch group/ungroup reparenting that preserves element order and
selection.
  * Coalesced panning and drag updates to reduce jitter.
* Connector/group indexing for more reliable updates, deletions and
sync.
  * Throttled viewport refresh behavior.

* **Documentation**
  * Docs added for RAF coalescer and measureOperation.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/framework/std/src/gfx/perf.ts

@@ -0,0 +1,31 @@
+let opMeasureSeq = 0;
+
+/**
+ * Measure operation cost via Performance API when available.
+ *
+ * Marks are always cleared, while measure entries are intentionally retained
+ * so callers can inspect them from Performance tools.
+ */
+export const measureOperation = <T>(name: string, fn: () => T): T => {
+  if (
+    typeof performance === 'undefined' ||
+    typeof performance.mark !== 'function' ||
+    typeof performance.measure !== 'function'
+  ) {
+    return fn();
+  }
+
+  const operationId = opMeasureSeq++;
+  const startMark = `${name}:${operationId}:start`;
+  const endMark = `${name}:${operationId}:end`;
+  performance.mark(startMark);
+
+  try {
+    return fn();
+  } finally {
+    performance.mark(endMark);
+    performance.measure(name, startMark, endMark);
+    performance.clearMarks(startMark);
+    performance.clearMarks(endMark);
+  }
+};