fix(release): override package name via extraMetadata for build templates (#49)

PR #47 added linux.executableName to fix snap's `--executable` flag
and the deb binary name — but the deb / snap output PATHS still come
from electron-builder's default artifactName templates which use the
${name} token (= package.json#name). That's now `@etherpad/desktop`
(scoped after the monorepo move), so:

- deb / snap write to `release/@etherpad/desktop_*` and crash with
  "Parent directory does not exist: release/@etherpad"
- Windows NSIS intermediate `release/@etherpaddesktop-*.nsis.7z`
  trips 7za's `@listfile` convention and fails with "Could not
  create destination file: No such file or directory"

Setting `extraMetadata.name: etherpad-desktop` in the
electron-builder config overrides package.json#name at build time
without touching the actual package.json (which we need to keep as
`@etherpad/desktop` for `pnpm --filter` and workspace deps). Every
artifact template that interpolates ${name} now sees the slash-free
name and the path issue goes away in one move.

Verified by inspecting the v0.4.1 build logs for both remaining
failures:
  - linux deb: fpm `--p ... cannot write to release/@etherpad/desktop_0.4.1_amd64.deb`
  - snap:      mksquashfs `Could not create destination file` on the
               same path shape (release/@etherpad/desktop_0.4.1_amd64.snap)
  - win nsis:  7za `Could not create destination file` on
               release\@etherpaddesktop-0.4.1-x64.nsis.7z (@-prefix
               triggers 7za's @ListFile mode)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: JohnMcLear

packages/desktop/build/electron-builder.yml

@@ -2,6 +2,19 @@ appId: org.etherpad.desktop
 productName: Etherpad Desktop
 copyright: Copyright (c) 2026 The Etherpad Foundation
 
+# Override the package.json#name (`@etherpad/desktop`) for build-time
+# artifact templating only. electron-builder uses `${name}` in
+# intermediate paths (deb, snap, the .nsis.7z that NSIS reads) and the
+# scoped name's `/` becomes a literal directory (deb/snap crash with
+# "Parent directory does not exist: release/@etherpad") while the `@`
+# prefix makes 7za interpret the .nsis.7z basename as a `@list-file`
+# argument ("Could not create destination file: No such file or
+# directory"). We can't drop the scope from package.json itself
+# without breaking `pnpm --filter @etherpad/desktop`, so override it
+# just for the build via extraMetadata.
+extraMetadata:
+  name: etherpad-desktop
+
 directories:
   buildResources: build
   output: release