chore(ci): add Go and templ setup to CI workflow

This update enhances the CI workflow by adding steps to set up Go using
the version specified in go.mod, add the Go bin directory to the PATH,
and install the templ code generation tool. These additions ensure that
Go-based tooling is available for subsequent CI steps.

.github/workflows/ci.yml

@@ -20,6 +20,17 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Add Go bin to PATH
+        run: echo "$(go env GOPATH)/bin" >> $GITHUB_PATH
+
+      - name: Install templ
+        run: go install github.com/a-h/templ/cmd/templ@v0.3.960
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3