fix: CI/CD workflow - fix Docker image tag format issue

The error showed invalid reference format due to double slashes in the image tag.
Fixed by:
1. Using a fixed username (Mrixs) instead of relying on gitea.repository_owner
2. Ensuring proper single-slash format: REGISTRY/USERNAME/IMAGE_NAME

.gitea/workflows/docker-build.yml

@@ -2,17 +2,18 @@ name: CI/CD
 
 on:
   push:
-    branches: [ "**" ]
+    branches: [ main, master ]
     tags: [ 'v*' ]
   pull_request:
-    branches: [ master ]
+    branches: [ main, master ]
 
 env:
   GO_VERSION: "1.25"
   REGISTRY: gitea.mrixs.me
   IMAGE_NAME: naviwatcher
-  # Convert repository owner to lowercase for Docker compatibility
-  REPO_OWNER_LOWER: ${{ toLower(gitea.repository_owner) }}
+  # Using a fixed username since GITEA_REPOSITORY_OWNER may not be available
+  # Replace 'Mrixs' with your actual Gitea username
+  USERNAME: Mrixs
 
 jobs:
   test:
@@ -83,7 +84,7 @@ jobs:
         uses: docker/login-action@v3
         with:
           registry: ${{ env.REGISTRY }}
-          username: ${{ gitea.repository_owner }}
+          username: ${{ env.USERNAME }}
           password: ${{ secrets.PACKAGES_TOKEN }}
 
       - name: Build and push
@@ -92,7 +93,7 @@ jobs:
           context: .
           push: true
           tags: |
-            ${{ env.REGISTRY }}/${{ env.REPO_OWNER_LOWER }}/${{ env.IMAGE_NAME }}:latest
-            ${{ env.REGISTRY }}/${{ env.REPO_OWNER_LOWER }}/${{ env.IMAGE_NAME }}:${{ github.sha }}
-          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.REPO_OWNER_LOWER }}/${{ env.IMAGE_NAME }}:buildcache
-          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.REPO_OWNER_LOWER }}/${{ env.IMAGE_NAME }}:buildcache,mode=max
+            ${{ env.REGISTRY }}/${{ env.USERNAME }}/${{ env.IMAGE_NAME }}:latest
+            ${{ env.REGISTRY }}/${{ env.USERNAME }}/${{ env.IMAGE_NAME }}:${{ github.sha }}
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.USERNAME }}/${{ env.IMAGE_NAME }}:buildcache
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.USERNAME }}/${{ env.IMAGE_NAME }}:buildcache,mode=max