ci: Use :latest tag instead of :main

- amd64: :latest and :sha-xxx
- arm64: :latest-arm64 and :sha-xxx-arm64

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/main.yml

@@ -37,8 +37,9 @@ jobs:
         uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
-          flavor: |
-            suffix=-arm64
+          tags: |
+            type=raw,value=latest,suffix=-arm64
+            type=sha,suffix=-arm64
 
       - name: Build and push Docker image (arm64)
         uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
@@ -76,6 +77,9 @@ jobs:
         uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=raw,value=latest
+            type=sha
 
       - name: Build and push Docker image (amd64)
         uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4