Migrate from Biome to Vite+ (oxfmt + oxlint)

[shunichironomura]

Summary

• Replace Biome with Vite+ for frontend linting and formatting (oxfmt + oxlint)
• Add pnpm-workspace.yaml with vite-plus catalogs and overrides
• Update vite.config.ts to use defineConfig from vite-plus with fmt and lint config
• Update justfile, CI workflow, and package.json scripts accordingly
• Auto-format all files with oxfmt

Test plan

• pnpm run vp:check passes (formatting + linting)
• pnpm run check passes (svelte-check)
• CI checks pass on GitHub

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