fix(release): point the download centers at the published installer

The download contract on both the web console and the landing site still
advertised 1.2.0, so the install button pointed at
D3RO-Voice-Setup-1.2.0-x64.exe, which the feed answers with 404 while 1.3.7
is live. Wire both contract files into version:sync so the installer version
and release date follow the version SSOT, and set them to the published 1.3.7.

💘 Generated with Crush

Assisted-by: Crush:deepseek-v4.1-flash

docs/map/02-infrastructure.md

@@ -199,6 +199,7 @@ Full detail: [`09-supabase-backend.md`](./09-supabase-backend.md).
 | `apps/desktop/electron-builder.yml` | appId `com.d3ro.voice`, NSIS x64 (forced code signing), macOS DMG/ZIP arm64, generic Forgejo publish feed, asarUnpack native modules + `@ffmpeg-installer`, extraResources (icons, sounds, sox, **sidecar**, ffmpeg, ollama) |
 | `apps/desktop/src/main/update-feed.ts` | Auto-update feed SSOT (canonical Forgejo + legacy GitLab mirror, channels) |
 | `release/update-policy.json` | Update policy SSOT (channels, minimum supported version, forced update, delta/full, staged rollout, kill switch) |
+| `apps/web/src/lib/desktop-release.ts`, `site/src/release.ts` | Download-center desktop release contract (installer filename + release date); version and date are kept on the SSOT by `npm run version:sync` (drifted to 1.2.0 once — GAP-REL-08) |
 | `apps/desktop/src/main/update-policy.ts` | Policy parsing/decision logic |
 | `scripts/ci/publish-forgejo-release.mjs` | Canonical Forgejo registry + Release + feed publisher |