chore(deps): TypeScript 7 upgrade tracker — workspace-wide migration from v5.9 #138

Umbrella tracker for the typescript 5.9.3 → 7.x workspace-wide upgrade, mirroring the pattern used for #115 (Astro) and #120 (Vitest).

Why this needs a tracker

Dependabot filed #135 (typescript 5.9.3 → 7.0.2) on 2026-08-13. TS 7 is a real migration, not a drop-in bump. The PR is already unstable — Type Check and verify both fail on the raw dep bump:

• Type Check: https://github.com/beeeku/workkit/actions/runs/31664672636/job/94336558985
• verify: https://github.com/beeeku/workkit/actions/runs/31664672651/job/94336559178

TypeScript 7 (following the native/Go rewrite that shipped as TS 6) tightens inference, changes several checker behaviours, and its native port has knock-on effects on every downstream tool that embeds tsc (tsup, tsx, vitest, wrangler, valibot's declaration emit, etc.). Merging as a single dep bump would break the workspace.

Scope

• typescript bump at the repo root (36+ packages consume it transitively)
• Fix any inference regressions surfaced by strict-mode + variance changes
• Verify each downstream tool still works with the new compiler: tsup, tsx, vitest (also on its own v4 upgrade tracker chore(deps): Vitest 4 upgrade tracker — workspace-wide migration from v3 #120), @cloudflare/workers-types (own tracker to be filed), Astro/Starlight typings (part of docs: Astro 5 → 7 upgrade tracker (apps/docs) #115)
• Update tsconfig defaults if TS 7 removes/renames flags we set

Blockers / coordination

• chore(deps): Vitest 4 upgrade tracker — workspace-wide migration from v3 #120 Vitest 4 tracker — check whether Vitest 4 also requires or supports TS 7 before landing either.
• docs: Astro 5 → 7 upgrade tracker (apps/docs) #115 Astro 7 tracker — Astro 7 ships its own type surface; land in whichever order avoids a double type-audit.
• Cloudflare workers-types v5 (separate tracker) — v5 targets newer TS features and might interact.

Action items

• Root bump typescript and observe every failing packages/* bun run type-check
• Fix inference regressions per-package (diff-only, per constitution rule 8)
• Confirm bundle sizes unchanged (bundle-size CI job)
• Confirm all bun test suites pass
• Close chore(deps-dev): bump typescript from 5.9.3 to 7.0.2 #135 (superseded by this tracker)

Dependabot handling (once accepted)

Extend the root bun ecosystem ignore: block in .github/dependabot.yml:

- dependency-name: typescript
  update-types:
    - version-update:semver-major

Follow the pattern established by #124 (dependabot config) and #137 (docs Astro-ecosystem ignore expansion).

Not covered here

• TS 6.x patch/minor bumps — those can flow through Dependabot normally.
• Editor/tsserver ergonomics (LSP consumers pick their own TS).