Add selected expression mini trace

[rogierx]

Summary

• add a Tracer: Measure selected expression command for TypeScript editors
• measure the active selection or cursor identifier with tsserver quick info and completions timings
• report averaged quick info/completion durations using the existing benchmark iteration setting
• remove shared pnpm cache from the tag-triggered release workflow

Addresses #44.

Validation

• pnpm exec vitest run test/index.test.ts
• pnpm run typecheck
• pnpm exec eslint src/miniTrace.ts src/miniTraceReport.ts src/commands.ts src/constants.ts scripts/generate-contributes.ts test/index.test.ts
• pnpm exec nuxt build ui
• pnpm exec rollup -c
• git diff --check