SEV-1: Release builds unsigned on macOS and Windows; release.yml doesn't fail-fast on missing artifacts

[iLevyTate]

Summary

src-tauri/tauri.conf.json:77-94 ships with null macOS signingIdentity and null Windows certificateThumbprint (with empty timestampUrl). Release workflow doesn't fail-fast on missing artifact uploads.

Status (after ae7b1f0)

Done:

• Removed continue-on-error: true from every artifact upload step in .github/workflows/release.yml. A missing .deb, .AppImage, .msi, or .dmg now fails the job — no more silent half-releases.
• Fixed the workflow's Ubuntu dep list: it referenced libwebkit2gtk-4.0-dev which is gone from ubuntu-24.04 runners. Now matches ci.yml's 4.1 stack (libwebkit2gtk-4.1-dev, libjavascriptcoregtk-4.1-dev, libsoup-3.0-dev, libayatana-appindicator3-dev, librsvg2-dev, patchelf).
• Documented required signing secrets in release.yml env block.

Still TODO (needs repo-admin action, not code):

macOS — add these repo secrets, then set signingIdentity in tauri.conf.json:

• APPLE_CERTIFICATE (base64 of .p12)
• APPLE_CERTIFICATE_PASSWORD
• APPLE_SIGNING_IDENTITY (e.g. Developer ID Application: Your Name (TEAMID))
• APPLE_ID, APPLE_TEAM_ID, APPLE_APP_SPECIFIC_PASSWORD for notarization

Windows — add these repo secrets, then set certificateThumbprint + a real timestampUrl (e.g. http://timestamp.digicert.com) in tauri.conf.json:

• WINDOWS_CERTIFICATE (base64 of .pfx)
• WINDOWS_CERTIFICATE_PASSWORD

Reopen / re-scope this issue once secrets are provisioned.