Adopt Ultracite lint baseline

[sarthakagrawal927]

Summary

• add exact dev-only ultracite@7.10.2
• extend the core, React, Next.js, and Vitest Ultracite presets
• preserve existing behavior through explicit compatibility exceptions and generated/static exclusions
• record the shipped baseline in PROJECT_STATUS.md

The initial run reported 2,232 diagnostics. The configured baseline now checks 206 files with zero errors or warnings and does not rewrite product source.

Validation

• pnpm exec ultracite check . (206 files, 0 diagnostics)
• pnpm exec biome format . (195 files)
• pnpm run typecheck
• pnpm run test:coverage (35 files, 170 tests; 100% statements/branches/functions/lines on the selective coverage surface)
• pnpm run docs:check (56 Markdown files)
• pnpm run build (31 static pages)
• git diff --check

Dependency-health evidence: pnpm audit reports no known vulnerabilities. Strict Knip still reports 2 unused exports, 1 unused exported type, and pre-existing configuration hints.

No deploy, migration, secret, production dependency, production configuration, embedding contract, or generated Worker output changed.

Closes #69
Supports sass-maker/fleet-workspace#249