feat: migrate Docker base image from Debian to Alpine for improved security and reduced size

.github/workflows/docker-build.yml

@@ -112,12 +112,12 @@ jobs:
       - name: Set up Docker Buildx
         if: steps.skip.outputs.skip_build != 'true'
         uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3.12.0
-      - name: Resolve Debian base image digest
+      - name: Resolve Alpine base image digest
         if: steps.skip.outputs.skip_build != 'true'
         id: caddy
         run: |
-          docker pull debian:trixie-slim
-          DIGEST=$(docker inspect --format='{{index .RepoDigests 0}}' debian:trixie-slim)
+          docker pull alpine:3.23.3
+          DIGEST=$(docker inspect --format='{{index .RepoDigests 0}}' alpine:3.23.3)
           echo "image=$DIGEST" >> $GITHUB_OUTPUT
 
       - name: Log in to GitHub Container Registry
@@ -744,7 +744,7 @@ jobs:
             -p 80:80 \
             ${{ env.GHCR_REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.tag.outputs.tag }}
 
-          # Wait for container to be healthy (max 3 minutes - Debian needs more startup time)
+          # Wait for container to be healthy (max 3 minutes)
           echo "Waiting for container to start..."
           timeout 180s bash -c 'until docker exec test-container curl -sf http://localhost:8080/api/v1/health 2>/dev/null | grep -q "status"; do echo "Waiting..."; sleep 2; done' || {
             echo "❌ Container failed to become healthy"