CHORE(app): switch to Gitea container registry

- Migrate from ghcr.io to Gitea registry
- Update image references

.gitea/workflows/build.yml

@@ -8,7 +8,7 @@ on:
   workflow_dispatch:
 
 env:
-  REGISTRY: ghcr.io
+  REGISTRY: gitea0213.kro.kr
   IMAGE_NAME: ${{ github.repository }}
   DOCKER_HOST: tcp://172.17.0.1:2375
 
@@ -27,14 +27,14 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Log in to GitHub Container Registry
+      - name: Log in to Gitea Container Registry
         run: |
-          echo "${{ secrets.githubregistry }}" | docker login ${{ env.REGISTRY }} -u Mayne0213 --password-stdin
+          echo "${{ secrets.GITEA_TOKEN }}" | docker login ${{ env.REGISTRY }} -u bluemayne --password-stdin
 
       - name: Lowercase repository name
         id: lowercase
         run: |
-          echo "repo=$(echo ${{ github.repository }} | tr '[:upper:]' '[:lower:]' | sed 's/bluemayne/mayne0213/')" >> $GITHUB_OUTPUT
+          echo "repo=$(echo ${{ github.repository }} | tr '[:upper:]' '[:lower:]')" >> $GITHUB_OUTPUT
 
       - name: Extract metadata (tags, labels)
         id: meta