[a5768549]

AI assistance disclosure: Hermes Agent assisted with the code, tests, and this description. The operator authorized this draft submission; it remains pending human code review and macOS packaging validation.

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

Addresses the DMG case in #3523.

Use forgeConfig.packagerConfig.appVersion || packageJSON.version in the default DMG artifact name, matching Packager's fallback for an absent or empty appVersion. An explicit MakerDMG name still takes precedence; the architecture-specific output directory and installer options are unchanged. Other makers are outside this PR's scope.

Verification

• New regression cases fail on the unmodified source (4 failed / 6 passed) and pass with the fix (10 passed). Tests cover the override, missing/empty fallback and custom-name precedence; installer/filesystem operations are mocked.
• yarn test:fast packages/maker: 14 files / 138 tests passed, independently rerun after review.
• yarn build, scoped oxfmt --check, oxlint, and git diff --check passed.
• Full yarn test:fast: 715 passed, 2 failed, 6 todo. Both failures are Vite configuration tests expecting fixed ports (5173/5183) that were occupied locally; the same failures were reproduced with the unmodified production source. The full-suite checkbox is therefore left unchecked.

Tested on Windows with Node 24.19.0 and Yarn 4.18.0 against main at 16d47dc2. No real DMG was created or mounted on macOS, including no real MAS/architecture packaging matrix; this is why the PR is a draft. The branch merges cleanly with fdb682ce.