Fix k3s deployment to use correct Docker image tag

The deployment was using raw SHA but the Docker metadata action creates
tags with 'main-' prefix for the main branch. Updated kubectl command
to use the correct tag format: main-${github.sha}

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/deploy.yml

@@ -64,7 +64,7 @@ jobs:
 
       - name: Deploy to K3s
         run: |
-          kubectl set image deployment/aprs aprs=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.sha }} -n aprs
+          kubectl set image deployment/aprs aprs=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:main-${{ github.sha }} -n aprs
 
       - name: Wait for rollout
         run: |