Fix release packaging

[EleventhLucas]

Summary

Fixes the first post-merge Release workflow failure and completes the release package metadata.

• Writes a real trailing newline when temporarily setting the release package version, keeping package.json valid on Windows.
• Sets a non-personal Debian maintainer so .deb packaging does not require an author email.
• Ships the repository license and a privacy notice in release artifacts.

Root cause

The release workflow wrote the two literal characters \\n after package.json, which made Windows E2E fail to parse it. Linux packaging then failed because Electron Builder requires either an author email or an explicit Debian maintainer.

Validation

• Exact release package-version rewrite parsed successfully and ended with a real newline.
• npm run typecheck
• npm run prepare:codex && npm run package:linux -- --publish never
• Verified the generated .deb contains resources/notices/LICENSE and resources/notices/PRIVACY.md.

The Windows path is covered by the PR CI matrix; the change removes the shell-escaping ambiguity that caused its prior JSON parse failure.