[react-strict-animated] add perf benchmarks for render and start paths

[vincentriemer]

[react-strict-animated] add perf benchmarks for render and start paths

Summary

• Add perf harness for react-strict-animated (rollup build, entrypoint, jsdom helpers)
• Implement animated render and animation start benchmarks
• Add stylex mock for perf bundle and wire new suites into perf runner
• Add jsdom to benchmarks deps

Testing

• npm run format
• npm run lint:report
• npm run flow
• npm run perf --workspace benchmarks

[github-actions]

workflow: benchmarks/size

Comparison of minified (terser) and compressed (brotli) size results, measured in bytes. Smaller is better.

Results	Base	Patch	Ratio
react-strict-dom/dist/web/index.js
· compressed	3,251	3,251	1.00
· minified	10,375	10,375	1.00
react-strict-dom/dist/web/runtime.js
· compressed	1,645	1,645	1.00
· minified	4,131	4,131	1.00
react-strict-dom/dist/native/index.js
· compressed	16,555	16,555	1.00
· minified	64,094	64,094	1.00
react-strict-animated/dist/web/index.js
· compressed	6,861	6,861	1.00
· minified	23,486	23,486	1.00
react-strict-animated/dist/native/index.js
· compressed	797	797	1.00
· minified	2,518	2,518	1.00

[github-actions]

workflow: benchmarks/perf (native)

Comparison of performance test results, measured in operations per second. Larger is better.

Results	Base	Patch	Ratio
css.create
· small	1,133,080	1,121,097	0.99	-
· small with units	494,213	487,203	0.99	-
· small with variables	664,854	662,142	1.00	-
· several small	352,428	347,188	0.99	-
· large	200,009	198,812	0.99	-
· large with polyfills	151,286	148,142	0.98	-
· complex	104,013	102,845	0.99	-
· unsupported	209,177	208,972	1.00	-
css.createTheme
· simple theme	226,544	223,445	0.99	-
· polyfill theme	212,863	210,616	0.99	-
animated.render
· mount small		602
· mount medium		355
· mount large		274
· update small		663
· update medium		654
· update large		633
animated.start
· timing start		13,993
· spring start		9,114
· parallel start		4,154
· sequence start		25,316