ci(deps): hold Electron at 43 while armv7l Linux packages ship (#1925)

Electron 44 publishes no linux-armv7l binary, so the 44.x update fails
the Linux packaging jobs on the armv7l AppImage, DEB and Snap targets.
Ignore Electron majors in Dependabot until 32-bit ARM support is
dropped deliberately; 43.x minor and patch updates still arrive.

Co-authored-by: 4gray <fourgray@proton.me>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture/workspace-shell.md

@@ -878,6 +878,9 @@ Toolchain notes for the Electron 43 baseline:
    Those dependencies require standalone PRs so their dedicated package,
    worker, playback, and diagnostic-contract validation cannot be hidden by an
    unrelated grouped update.
+   Electron majors are ignored: Electron 44 ships no `linux-armv7l` binary,
+   and the release still packages armv7l AppImage, DEB and Snap builds. Remove
+   the ignore together with those targets when 32-bit ARM support is dropped.
 4. Electron 42 and newer download their development binary on the first
    Electron command instead of during package `postinstall`, so `electron`
    must not remain in pnpm's `onlyBuiltDependencies` allowlist. The first local