fix: add desktop linux package metadata

[rogerchappel]

Summary

• add homepage, author email, and Linux maintainer metadata required by Electron Builder .deb packaging
• call electron-builder directly in the release workflow so matrix args are passed cleanly

Failure addressed

The validation run https://github.com/rogerchappel/crewcmd/actions/runs/25226685646 packaged macOS and Windows successfully, but Linux x64/arm64 failed while building .deb because homepage, author email, and maintainer metadata were missing.

Verification

• git diff --check
• workflow YAML parse
• pnpm install --frozen-lockfile in apps/desktop
• pnpm check in apps/desktop
• pnpm exec tsc --noEmit --pretty false
• CSC_IDENTITY_AUTO_DISCOVERY=false pnpm exec electron-builder --dir --publish never in apps/desktop

Risk

Low. Metadata-only package fix plus safer workflow command argument handling.