E2E: Remove perf regression harness from this PR.

The perf-regression scripts belong in a separate PR (or stay as personal
tooling); this PR should be scoped to the renderer allocation fixes only.
Drops `test/e2e/perf-regression.js`, `test/e2e/perf-regression-compare.js`,
their README section, and the corresponding `.gitignore` entry.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: RenaudRohlinger

.gitignore

@@ -11,7 +11,6 @@ npm-debug.log
 
 test/e2e/chromium
 test/e2e/output-screenshots
-test/e2e/perf-regression-*.json
 test/treeshake/index.bundle.js
 test/treeshake/index.bundle.min.js
 test/treeshake/index.webgpu.bundle.js

test/e2e/README.md

@@ -39,22 +39,3 @@ Merge only those commits that pass the tests, otherwise all next commits will al
 
 ### Status
 97% examples are covered with tests. Check exception list for more information.
-
-### Perf & VRAM regression
-
-`perf-regression.js` measures JS heap, GC, frame timing, and WebGPU resource deltas for a given example. Useful for catching VRAM leaks, GC churn increases, or frame-time regressions introduced by a renderer change. The WebGPU device is wrapped in a page-side interceptor; no external tooling required.
-
-```shell
-# capture a baseline on one branch
-node test/e2e/perf-regression.js baseline webgpu_backdrop_water
-
-# switch branches, capture the candidate
-node test/e2e/perf-regression.js candidate webgpu_backdrop_water
-
-# compare
-node test/e2e/perf-regression-compare.js baseline candidate webgpu_backdrop_water
-```
-
-Each run produces `test/e2e/perf-regression-<label>-<example>.json`. Optional args: `durationMs` (default 10000), `warmupMs` (default 3000).
-
-Single-run numbers have measurement noise — for regression signals below ~5%, average 3 runs per branch (different `<label>` each run, then average the fields manually). Frame `p50/p95/p99/max`, JS heap `mean`/`max`, `gc.totalFreedBytes`, and all WebGPU resource deltas are the most repeatable signals.