Update typescript to 6.0.3

[EricWittmann]

Summary

• Update typescript from 5.9.3 to 6.0.3

Context

This dependency upgrade was split from Renovate PR #26 for easier review and testing.

Test Plan

• Build passes
• Tests pass
• No breaking changes detected

[EricWittmann]

Review Summary

This PR upgrades TypeScript from 5.9.3 to 6.0.3 — a major version bump. The changes are limited to package.json and package-lock.json, which is expected for a dependency-only upgrade.

---

Findings

⚠️ Warning

Major version upgrade — verify build and tests

package.json — typescript: 5.9.3 → 6.0.3

TypeScript 6.x is a major version bump and may include breaking changes to type checking, compiler behavior, or deprecated option removal. The PR description includes a test plan with unchecked boxes (build passes, tests pass, no breaking changes). Please confirm these have been validated before merging — particularly:

• The project compiles cleanly with tsc (the build script).
• All tests pass via vitest run.
• No new type errors are introduced in src/.

The tsconfig.json settings (module: "Node16", moduleResolution: "Node16", target: "ES2022", strict: true) are standard and likely compatible, but it's worth confirming no compiler options have been deprecated or had their behavior changed in TS 6.x.

💬 Nitpick

Unrelated lockfile changes

package-lock.json — removal of libc arrays from @biomejs/biome platform packages

The lockfile diff includes the removal of libc constraints from four @biomejs/biome optional platform-specific packages (cli-linux-arm64, cli-linux-arm64-musl, cli-linux-x64, cli-linux-x64-musl). These are unrelated to the TypeScript upgrade and are likely a side effect of lockfile regeneration (e.g., a different npm version or npm install normalizing the lockfile format). This is harmless but worth noting for traceability.

---

Overall Assessment

✅ Looks good to merge — once the build and test plan items are confirmed passing. The change is well-scoped and the PR description clearly explains the intent and origin (split from Renovate PR #26). No source code changes are involved, so the risk is limited to compiler compatibility, which should be caught by CI.