fix: Install Rust via rustup in CI

.gitea/workflows/ci.yml

@@ -13,5 +13,8 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
-      - name: Verify Rust
+      - name: Install Rust
-        run: cargo --version
+        run: |
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
+          . "$HOME/.cargo/env"
+          cargo --version