fix(build): use sharp prebuilt instead of compiling from source (fixes macOS CI)

.github/workflows/build.yml

@@ -69,6 +69,15 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
+      # ─── Ensure sharp prebuilt binary (+ bundled libvips) ─────
+      # `npm ci` can leave sharp without its prebuilt binary/vendored libvips,
+      # which makes electron-builder's native rebuild fail ("vips-cpp.42 not
+      # found"). Re-fetch the prebuilt (never compile from source).
+      - name: Ensure sharp prebuilt
+        run: npm rebuild sharp
+        env:
+          npm_config_build_from_source: "false"
+
       # ─── Import Code Signing Certificate ──────────────────────
       # This is the KEY step that makes CI signing work.
       # We create a temporary keychain, import the .p12 cert into it,