Build workspace packages after their devDependencies

[jzongker]

Summary

• Switch the root build script from --topological to --topological-dev so @churchapps/helpers (a devDependency of apihelper/apphelper) is compiled before those packages. This unblocks CI's "Build all packages (topological)" step, which has been failing with TS2307: Cannot find module '@churchapps/helpers' since before the 2026-08-16 wave.
• Wrap PUBLIC_CONTENT_TYPE_PREFIXES in apihelper/src/helpers/S3UploadPolicy.ts so the 8-item array satisfies array-bracket-newline (wave-introduced lint error from Constrain S3 upload ACL and types #16).

Test plan

• Fresh workspace build (topological-dev) from empty dist folders — pass
• apihelper eslint on src/ — 0 errors
• Root lint (lint:check foreach) — pass
• workspace @churchapps/apphelper test — 5 files / 32 tests
• workspace @churchapps/integration-sdk test — 4 files / 26 tests
• apihelper tests (incl. S3 policy + disk path guards) — 33 pass
• helpers tests — 53 pass

Do not merge from this PR unless you intend to; this is the lint/CI-build fix only.