chore(lint): add oxlint checks

[gregkonush]

Summary

• add root Oxlint config/ignores plus scripts and deps (with a type-aware pilot in services/bumba)
• wire non-blocking Oxlint steps into the bumba CI via the common monorepo workflow
• document the dual Biome/Oxlint workflow and tsgolint constraints

Related Issues

Closes #2198

Testing

• bunx biome check package.json services/bumba/package.json README.md .oxlintrc.json .github/workflows/common-monorepo.yml .github/workflows/bumba-ci.yml
• bun run lint:oxlint
• bun run lint:oxlint:type
• bun run --cwd services/bumba tsc
• bun run --cwd services/bumba test

Breaking Changes

None

Checklist

• Testing section documents the exact validation performed (or N/A with justification).
• Screenshots and Breaking Changes sections are handled appropriately (removed or filled in).
• Documentation, release notes, and follow-ups are updated or tracked.

[gregkonush]