electron-builder.cjs hardcodes config — `--mac dir` CLI flag is a no-op

packages/spotlight/electron-builder.cjs calls builder.build({config:{mac...}}) directly with a hardcoded config object, so passing --mac dir (or any other CLI target flag) has no effect — it's silently ignored. Trap: this looks like a valid way to force the mac/DMG target when testing build:mac locally on a Linux host, but electron-builder still resolves platform targets from the hardcoded config plus host-OS defaults (snap/AppImage on Linux), not the CLI. Consequence for verification: a true mac/DMG target build can only be exercised on macOS; on Linux you can only confirm a fix reaches the target-building stage without erroring earlier (e.g. past the fileMatcher/minimatch step), not that DMG packaging itself succeeds.