Use shell-based check-before-install for all build jobs

Replace JS-based GitHub Actions (dtolnay/rust-toolchain,
actions/setup-node) in the Linux job with shell commands that
check if Rust and Node.js are already present before installing.
All three jobs (Linux, macOS, Windows) now use the same pattern:
skip installation if the tool is already available on the runner.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/build-app.yml

@@ -61,17 +61,29 @@ jobs:
             xdg-utils
 
       - name: Install Rust stable
-        uses: dtolnay/rust-toolchain@stable
-
-      - name: Rust cache
-        uses: swatinem/rust-cache@v2
-        with:
-          workspaces: "./app/src-tauri -> target"
+        run: |
+          if command -v rustup &>/dev/null; then
+            echo "Rust already installed: $(rustc --version)"
+            rustup update stable
+            rustup default stable
+          else
+            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable
+            . "$HOME/.cargo/env"
+          fi
+          rustc --version
+          cargo --version
 
       - name: Install Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: "22"
+        run: |
+          if command -v node &>/dev/null; then
+            echo "Node.js already installed: $(node --version)"
+          else
+            echo "Installing Node.js 22..."
+            curl -fsSL https://deb.nodesource.com/setup_22.x | sudo -E bash -
+            sudo apt-get install -y nodejs
+          fi
+          node --version
+          npm --version
 
       - name: Install frontend dependencies
         working-directory: ./app
@@ -122,6 +134,18 @@ jobs:
   build-macos:
     runs-on: macos-latest
     steps:
+      - name: Install Node.js
+        run: |
+          if command -v node &>/dev/null; then
+            echo "Node.js already installed: $(node --version)"
+          else
+            echo "Installing Node.js 22 via Homebrew..."
+            brew install node@22
+            brew link --overwrite node@22
+          fi
+          node --version
+          npm --version
+
       - name: Checkout
         uses: actions/checkout@v4
         with:
@@ -144,19 +168,17 @@ jobs:
           echo "Patched version to ${VERSION}"
 
       - name: Install Rust stable
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          targets: aarch64-apple-darwin,x86_64-apple-darwin
-
-      - name: Rust cache
-        uses: swatinem/rust-cache@v2
-        with:
-          workspaces: "./app/src-tauri -> target"
-
-      - name: Install Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: "22"
+        run: |
+          if command -v rustup &>/dev/null; then
+            rustup update stable
+            rustup default stable
+          else
+            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable
+            . "$HOME/.cargo/env"
+          fi
+          rustup target add aarch64-apple-darwin x86_64-apple-darwin
+          rustc --version
+          cargo --version
 
       - name: Install frontend dependencies
         working-directory: ./app
@@ -168,6 +190,8 @@ jobs:
 
       - name: Build Tauri app (universal)
         working-directory: ./app
+        env:
+          PATH: ${{ format('{0}/.cargo/bin:{1}', env.HOME, env.PATH) }}
         run: npx tauri build --target universal-apple-darwin
 
       - name: Collect artifacts

BUILDING.md

@@ -1,6 +1,6 @@
 # Building Triple-C
 
-Triple-C is a Tauri v2 desktop application with a React/TypeScript frontend and a Rust backend. This guide covers building the app from source on Linux and Windows.
+Triple-C is a Tauri v2 desktop application with a React/TypeScript frontend and a Rust backend. This guide covers building the app from source on Linux, macOS, and Windows.
 
 ## Prerequisites (All Platforms)
 
@@ -79,6 +79,57 @@ Build artifacts are located in `app/src-tauri/target/release/bundle/`:
 | Debian pkg | `deb/*.deb`                   |
 | RPM pkg    | `rpm/*.rpm`                   |
 
+## macOS
+
+### 1. Install prerequisites
+
+- **Xcode Command Line Tools** — required for the C/C++ toolchain and system headers:
+
+```bash
+xcode-select --install
+```
+
+No additional system libraries are needed — macOS includes WebKit natively.
+
+### 2. Install Rust targets (universal binary)
+
+To build a universal binary that runs on both Apple Silicon and Intel Macs:
+
+```bash
+rustup target add aarch64-apple-darwin x86_64-apple-darwin
+```
+
+### 3. Install frontend dependencies
+
+```bash
+cd app
+npm ci
+```
+
+### 4. Build
+
+For a universal binary (recommended for distribution):
+
+```bash
+npx tauri build --target universal-apple-darwin
+```
+
+For the current architecture only (faster, for local development):
+
+```bash
+npx tauri build
+```
+
+Build artifacts are located in `app/src-tauri/target/universal-apple-darwin/release/bundle/` (or `target/release/bundle/` for single-arch builds):
+
+| Format | Path |
+|--------|------|
+| DMG | `dmg/*.dmg` |
+| macOS App | `macos/*.app` |
+| macOS App (compressed) | `macos/*.app.tar.gz` |
+
+> **Note:** The app is not signed or notarized. On first launch, macOS Gatekeeper may block it. Right-click the app and select "Open" to bypass, or remove the quarantine attribute: `xattr -cr /Applications/Triple-C.app`
+
 ## Windows
 
 ### 1. Install prerequisites