Add testing skill for StreamKit compositor UI #222

Job	Run time
Skit / Lint (fmt + clippy)	6m 3s
E2E / Playwright E2E	6m 53s
Skit / Build	18m 23s
Skit / Test	10m 39s
UI / Build	31s
Plugins / Format Check	17s
Plugins / Lint (Simple Plugins)	41s
Plugins / Lint (Sherpa-ONNX Plugins)	45s
Plugins / Lint (Whisper)	1m 19s
Plugins / Lint (NLLB)	2m 17s
UI / Test	23s
UI / Lint (TypeScript + ESLint)	37s
All Checks Passed	0s
	48m 48s

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