chore: Enhance GPG key handling in GitHub Actions workflow

- Updated GPG key import process to decode the key from base64 before importing.
- Added setup steps for GPG configuration, including loopback pinentry settings and restarting the gpg-agent.
- Improved GPG signing support to ensure secure artifact signing during deployment.

Author: Marvin Zhang

.github/workflows/publish.yml

@@ -74,10 +74,18 @@ jobs:
 
       - name: Import GPG key
         run: |
-          echo "${{ secrets.GPG_PRIVATE_KEY }}" | gpg --batch --import
+          echo "${{ secrets.GPG_PRIVATE_KEY }}" | base64 -d | gpg --batch --import
+          gpg --list-secret-keys --keyid-format LONG
         env:
           GPG_PRIVATE_KEY: ${{ secrets.GPG_PRIVATE_KEY }}
 
+      - name: Set up GPG
+        run: |
+          echo "allow-loopback-pinentry" >> ~/.gnupg/gpg-agent.conf
+          echo "pinentry-mode loopback" >> ~/.gnupg/gpg.conf
+          gpgconf --kill gpg-agent
+          gpg-agent --daemon
+
       - name: Set GPG_TTY
         run: echo "GPG_TTY=$(tty)" >> $GITHUB_ENV