v1.13.2

Maintenance release. The manifest changelog field and the letterboxdsync.dev Releases page now match the v1.0–v1.12 single-paragraph user-facing prose style after v1.13.0 (rendered as a multi-paragraph incident report) and v1.13.1 (rendered as the raw conventional-commit subject line) drifted away from it. The release workflow now pulls the manifest changelog from a ## Release notes section in the merged PR's body via the GitHub API, so the prose that lands in users' plugin catalogs is deliberate and reviewable. Backfills the two missing structured entries on the Releases page and rewrites the two stale manifest entries inline. No plugin behaviour changes.