Add optimized multi-platform release CI/CD pipeline.

Split Windows builds into shared x64 prep and arch-specific packaging, add comprehensive caching, verification scripts, and a PR smoke workflow.

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/actions/cache-cargo-windows/action.yml

@@ -0,0 +1,16 @@
+name: Cache Cargo (windows-setup)
+description: Cache registry, git sources, and target/ for the Windows installer Rust workspace
+
+runs:
+  using: composite
+  steps:
+    - name: Cache Cargo
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+          app/desktop/windows-setup/target
+        key: cargo-windows-${{ runner.os }}-${{ hashFiles('app/desktop/windows-setup/Cargo.lock', 'app/desktop/windows-setup/**/*.rs') }}
+        restore-keys: |
+          cargo-windows-${{ runner.os }}-

.github/actions/set-version/action.yml

@@ -0,0 +1,14 @@
+name: Set release version
+description: Writes versionName/versionCode into build.gradle.kts for CI
+
+inputs:
+  version:
+    description: Semantic version (e.g. 1.2.3)
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Set version
+      shell: bash
+      run: bash scripts/ci-set-version.sh "${{ inputs.version }}"

.github/actions/setup-java-gradle/action.yml

@@ -0,0 +1,23 @@
+name: Setup Java and Gradle
+description: Temurin JDK 17 + Gradle wrapper with dependency and build cache
+
+inputs:
+  java-architecture:
+    description: Optional JDK architecture (x64, arm64, …)
+    required: false
+    default: ""
+
+runs:
+  using: composite
+  steps:
+    - uses: actions/setup-java@v4
+      with:
+        distribution: temurin
+        java-version: "17"
+        architecture: ${{ inputs.java-architecture }}
+
+    - uses: gradle/actions/setup-gradle@v4
+      with:
+        gradle-version: wrapper
+        cache-read-only: false
+        add-job-summary: true