refactor: separate Rust installation step in build workflow

.gitea/workflows/build.yaml

@@ -14,12 +14,18 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y \
-            build-essential git ca-certificates curl tar gzip \
+            build-essential git ca-certificates curl tar gzip
-            rustc cargo
 
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Install Rust (stable)
+        shell: bash
+        run: |
+          set -e
+          curl -fsSL https://sh.rustup.rs | sh -s -- -y --default-toolchain stable
+          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
+
       - name: Debug workspace
         shell: bash
         run: |