[WIP] Copilot cloud agent request

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

Original prompt

Migrate the dependency 'typescript' to 6.0.3 on a new branch and open ONE pull request titled 'chore(deps-major): migrate typescript to 6.0.3 2026-06-24'. This is a KNOWN BREAKING major bump — work through the migration carefully using this assessment as the spec:

TS 6.0 genuine major (tighter inference, removed legacy flags). Project uses tsc -b project-refs with strict + verbatimModuleSyntax. Expect a handful of new type errors to fix, not structural breakage; peers (@react-router/dev ^5.1||^6) allow it. Do alongside @types/node + zod 4 so type errors are diagnosed once.

Apply the code changes the breaking changes require, run the project's install + test/build, and make sure it is green before opening the PR. Keep the change scoped to THIS migration only (do not bump unrelated dependencies, do not refactor). Do NOT merge.