asdf

Squash the current repository state back into one baseline commit while
preserving the README reframing and repository contents.

Constraint: User explicitly requested a single squashed commit with subject "asdf"
Confidence: high
Scope-risk: broad
Reversibility: clean
Directive: This commit intentionally rewrites published history; coordinate before future force-pushes
Tested: git status clean; local history rewritten to one commit; force-pushed main to origin and instructkr
Not-tested: Fresh clone verification after push

src/utils/fpsTracker.ts

@@ -0,0 +1,47 @@
+export type FpsMetrics = {
+  averageFps: number
+  low1PctFps: number
+}
+
+export class FpsTracker {
+  private frameDurations: number[] = []
+  private firstRenderTime: number | undefined
+  private lastRenderTime: number | undefined
+
+  record(durationMs: number): void {
+    const now = performance.now()
+    if (this.firstRenderTime === undefined) {
+      this.firstRenderTime = now
+    }
+    this.lastRenderTime = now
+    this.frameDurations.push(durationMs)
+  }
+
+  getMetrics(): FpsMetrics | undefined {
+    if (
+      this.frameDurations.length === 0 ||
+      this.firstRenderTime === undefined ||
+      this.lastRenderTime === undefined
+    ) {
+      return undefined
+    }
+
+    const totalTimeMs = this.lastRenderTime - this.firstRenderTime
+    if (totalTimeMs <= 0) {
+      return undefined
+    }
+
+    const totalFrames = this.frameDurations.length
+    const averageFps = totalFrames / (totalTimeMs / 1000)
+
+    const sorted = this.frameDurations.slice().sort((a, b) => b - a)
+    const p99Index = Math.max(0, Math.ceil(sorted.length * 0.01) - 1)
+    const p99FrameTimeMs = sorted[p99Index]!
+    const low1PctFps = p99FrameTimeMs > 0 ? 1000 / p99FrameTimeMs : 0
+
+    return {
+      averageFps: Math.round(averageFps * 100) / 100,
+      low1PctFps: Math.round(low1PctFps * 100) / 100,
+    }
+  }
+}