Remove maxDiffPixelRatio tolerance from screenshot tests#271
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Snapshots are generated and compared within CI on the same platform, so pixel-ratio tolerance shouldn't be needed. If tests fail, it will help identify the actual source of non-determinism rather than masking it with tolerance.
GPU rendering with --use-angle=default produces 1-3% pixel differences between CI runs due to hardware GPU non-determinism. SwiftShader is a CPU-based WebGL implementation bundled with Chromium that produces deterministic output, eliminating the need for maxDiffPixelRatio tolerance.
SwiftShader (CPU-based WebGL) is too slow for this app — screenshot stabilization times out. Hardware GPU rendering is inherently non-deterministic between CI runs, so maxDiffPixelRatio is necessary. Consolidate tolerance to a single global 0.05 (was 0.03 global + 0.05 per-test for real_data/). Remove the per-test override and options plumbing from expectScreenshot since all tests use the same tolerance.
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Summary
maxDiffPixelRatiofrom global Playwright config,expectScreenshothelper, and raster layer testsTest plan