refactor: enhance build workflow with debugging and caching steps

.gitea/workflows/build.yaml

@@ -20,15 +20,40 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Debug workspace
+        shell: bash
+        run: |
+          set -e
+          pwd
+          ls -la
+
+      - name: Cache Cargo
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-
+
       - name: Read package name
         id: pkg_meta
         shell: bash
         run: |
           set -e
-          PKG_NAME="$(sed -n 's/^name = \"\\(.*\\)\"/\\1/p' Cargo.toml | head -n 1)"
-          if [ -z "$PKG_NAME" ]; then
-            echo "Could not read package name from Cargo.toml"
-            exit 1
+          if [ -f Cargo.toml ]; then
+            PKG_NAME="$(sed -n 's/^name = \"\\(.*\\)\"/\\1/p' Cargo.toml | head -n 1)"
+          fi
+          if [ -z "${PKG_NAME:-}" ]; then
+            FULL="${GITHUB_REPOSITORY:-}"
+            if [ -z "$FULL" ]; then
+              echo "Could not read Cargo.toml and GITHUB_REPOSITORY is empty"
+              exit 1
+            fi
+            PKG_NAME="${FULL##*/}"
+            echo "Cargo.toml missing or unreadable. Falling back to repo name: $PKG_NAME"
           fi
           echo "pkg_name=$PKG_NAME" >> "$GITHUB_OUTPUT"