feat(macos): build universal binary (Intel + Apple Silicon)

Cross-compile both aarch64-apple-darwin and x86_64-apple-darwin on the
existing macos-14 (arm64) runner, then `lipo` them into a single fat
binary before bundling. One signed/notarized DMG covers both Mac CPU
families: utter-VERSION-macos-universal.dmg.

Notarization is the slow/flaky step in this job and only runs once
either way, so the cost is the second `cargo build` (cached) plus
~doubled binary size — small relative to the model. The README's macOS
quickstart drops the "(Apple Silicon)" qualifier and points at the
new universal DMG name.

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

Author: jguice

.github/workflows/release.yml

@@ -155,15 +155,14 @@ jobs:
           if-no-files-found: error
 
   macos-build:
-    name: Build macOS arm64 (signed + notarized DMG)
+    name: Build macOS universal (signed + notarized DMG)
     needs: test
     runs-on: macos-14
     env:
       APPLE_ID: ${{ secrets.APPLE_ID }}
       APPLE_APP_PASSWORD: ${{ secrets.APPLE_APP_PASSWORD }}
       APPLE_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}
       UTTER_SIGN_IDENTITY: "Developer ID Application: Josh Guice (YKQ46WD7SL)"
-      RUST_TARGET: aarch64-apple-darwin
 
     steps:
       - name: Resolve checkout ref
@@ -186,12 +185,12 @@ jobs:
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@stable
         with:
-          targets: ${{ env.RUST_TARGET }}
+          targets: aarch64-apple-darwin,x86_64-apple-darwin
 
       - name: Cache cargo
         uses: Swatinem/rust-cache@v2
         with:
-          shared-key: release-macos-arm64
+          shared-key: release-macos-universal
 
       - name: Import Developer ID cert into temp keychain
         env:
@@ -220,12 +219,20 @@ jobs:
           security find-identity -v -p codesigning "$KEYCHAIN_PATH"
 
       - name: Build release binary (arm64)
-        run: cargo build --release --locked --target "$RUST_TARGET"
+        run: cargo build --release --locked --target aarch64-apple-darwin
+
+      - name: Build release binary (x86_64)
+        run: cargo build --release --locked --target x86_64-apple-darwin
 
-      - name: Stage binary for bundle
+      - name: Combine into universal binary
         run: |
+          set -euo pipefail
           mkdir -p target/release
-          cp "target/${RUST_TARGET}/release/utter" target/release/utter
+          lipo -create -output target/release/utter \
+            target/aarch64-apple-darwin/release/utter \
+            target/x86_64-apple-darwin/release/utter
+          lipo -info target/release/utter
+          file target/release/utter
 
       - name: Build + sign .app bundle
         run: ./scripts/make-bundle.sh
@@ -253,7 +260,7 @@ jobs:
           set -euo pipefail
           TAG="${DISPATCH_TAG:-$RAW_VERSION}"
           VERSION="${TAG#v}"
-          DMG_NAME="utter-${VERSION}-macos-arm64.dmg"
+          DMG_NAME="utter-${VERSION}-macos-universal.dmg"
           mkdir -p dist
           STAGE="$RUNNER_TEMP/dmg-stage"
           rm -rf "$STAGE"
@@ -274,7 +281,7 @@ jobs:
       - name: Sign + notarize + staple DMG
         run: |
           set -euo pipefail
-          DMG=$(ls dist/utter-*-macos-arm64.dmg)
+          DMG=$(ls dist/utter-*-macos-universal.dmg)
           codesign --force --sign "$UTTER_SIGN_IDENTITY" --timestamp "$DMG"
           xcrun notarytool submit "$DMG" \
             --apple-id "$APPLE_ID" \
@@ -287,8 +294,8 @@ jobs:
       - name: Upload DMG artifact
         uses: actions/upload-artifact@v4
         with:
-          name: dist-macos-arm64
-          path: dist/utter-*-macos-arm64.dmg
+          name: dist-macos-universal
+          path: dist/utter-*-macos-universal.dmg
           if-no-files-found: error
 
   release:

README.md

@@ -7,9 +7,9 @@ Local, no-cloud push-to-talk dictation for **macOS and Linux**. Hold a key, spea
 
 ## Quickstart
 
-### macOS (Apple Silicon)
+### macOS (Apple Silicon or Intel)
 
-1. Download `utter-VERSION-macos-arm64.dmg` from the [latest release](https://github.com/jguice/utter/releases/latest). Open it, drag `utter.app` to `/Applications`.
+1. Download `utter-VERSION-macos-universal.dmg` from the [latest release](https://github.com/jguice/utter/releases/latest). Open it, drag `utter.app` to `/Applications`.
 2. Fetch the speech model (~650 MB, one-time):
    ```bash
    curl -fsSL https://raw.githubusercontent.com/jguice/utter/main/scripts/download-model.sh | bash

docs/TROUBLESHOOTING.md

@@ -1,6 +1,6 @@
 # Troubleshooting (Linux)
 
-Everything below is Linux-specific. On macOS, check Console.app for messages tagged `utter` and open an issue if you hit something not covered by the [README quickstart's onboarding flow](../README.md#macos-apple-silicon).
+Everything below is Linux-specific. On macOS, check Console.app for messages tagged `utter` and open an issue if you hit something not covered by the [README quickstart's onboarding flow](../README.md#macos-apple-silicon-or-intel).
 
 **Nothing pastes after I release the key.**
 ```bash