0015. Frontend tooling: mise, pnpm, TypeScript 7, Biome, Vitest, Playwright

Decision

Piece	Choice	Why
Toolchain versions	mise (`mise.toml`: Go, Node LTS, pnpm)	`mise install` and you are done. CI uses the same file
Package manager	pnpm v12	Install scripts blocked by default; `minimumReleaseAge` refuses freshly published packages; strict `node_modules`
Type checking	TypeScript 7 (native compiler)	About 10× faster. Any tool that needs the old API stays on 5.x on its own
Lint + format	Biome v2	One tool instead of ESLint + Prettier + plugins + typescript-eslint
React Compiler	Its own build-time diagnostics	The build reports components it cannot optimize
Logic tests	Vitest v5	Native to Vite and fast
Component tests	Vitest browser mode (real Chromium) + MSW mocks generated by orval	A real browser instead of a simulated DOM
E2E	Playwright against the real binary	—
Accessibility	`@axe-core/playwright` in E2E	Serious violations fail CI
PWA	vite-plugin-pwa v2 (Workbox)	Caches only the app shell, never API data. Shows an update prompt
Bundle budget	size-limit	Less than 250 KB gzipped of initial JS
Dependency updates	Dependabot	Covers Go, npm, GitHub Actions and Docker (`.github/dependabot.yml`). Renovate was the first choice; replaced on 2026-11-10 because Dependabot is built into GitHub and needs no app install

The real binary starts with a temp data dir and seed data.
Telegram points to a fake Bot API server, reused from the Go tests.
The test advances the clock → the reminder arrives with its buttons.
It simulates “Change date” → 10 → “This charge only” → Confirm.
It asserts the message was re-edited and the open web page updated by itself via SSE.
axe runs on the result.