Cache lint and typecheck per workspace with Turborepo

lint and typecheck re-checked the whole repository on every run. They now run through Turborepo 2.11.9 with one task per workspace plus a root task, one at a time to respect the build slot. A workspace’s cache key covers its own files and the hashes of the workspaces it depends on, so a change re-checks only the workspaces that use it. Changing shared config such as eslint.config.mjs, tsconfig.base.json or bun.lock invalidates everything.

A cold bun run lint takes about 2.5 minutes. A rerun with no changes replays all 16 tasks from .turbo/ in 0.1 seconds. Missing dependency declarations the cache needed were added, and .turbo/ is ignored. Run with -- --force to bypass the cache.