fix(ci): install Rust in hub-check for shipping cph

hub-check builds cph via cargo install; the runner image has no rustup.
Mirror checker-check's dtolnay/rust-toolchain + cargo cache.

.gitea/workflows/hub-check.yml

@@ -34,6 +34,20 @@ jobs:
     steps:
       - uses: actions/checkout@v5
 
+      - name: Install Rust toolchain (for cph binary)
+        uses: dtolnay/rust-toolchain@1.92.0
+
+      - name: Cache cargo registry + build
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: cargo-hub-check-${{ runner.os }}-${{ hashFiles('Cargo.lock') }}
+          restore-keys: |
+            cargo-hub-check-${{ runner.os }}-
+
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with: