FIX(ci): fix Gitea Actions context variables

- Use github.* instead of gitea.* context
- Fix workflow variable references

.gitea/workflows/build.yml

@@ -9,7 +9,7 @@ on:
 
 env:
   REGISTRY: gitea0213.kro.kr
-  IMAGE_NAME: ${{ gitea.repository }}
+  IMAGE_NAME: ${{ github.repository }}
 
 jobs:
   build-and-push:
@@ -33,13 +33,13 @@ jobs:
         uses: docker/login-action@v3
         with:
           registry: ${{ env.REGISTRY }}
-          username: ${{ gitea.actor }}
+          username: ${{ github.actor }}
           password: ${{ secrets.GITEA_TOKEN }}
 
       - name: Lowercase repository name
         id: lowercase
         run: |
-          echo "repo=$(echo ${{ gitea.repository }} | tr '[:upper:]' '[:lower:]')" >> $GITHUB_OUTPUT
+          echo "repo=$(echo ${{ github.repository }} | tr '[:upper:]' '[:lower:]')" >> $GITHUB_OUTPUT
 
       - name: Extract metadata (tags, labels)
         id: meta
@@ -77,10 +77,10 @@ jobs:
           echo "---"
 
           # Get commit SHA (full 40 characters)
-          COMMIT_SHA="${{ gitea.sha }}"
+          COMMIT_SHA="${{ github.sha }}"
 
           # Get current branch name
-          BRANCH_NAME="${{ gitea.ref_name }}"
+          BRANCH_NAME="${{ github.ref_name }}"
           echo "Branch: $BRANCH_NAME"
 
           # Method 1: Extract the full SHA tag from docker/metadata-action output
@@ -124,7 +124,7 @@ jobs:
           fi
 
           # Determine overlay based on branch
-          BRANCH_NAME="${{ gitea.ref_name }}"
+          BRANCH_NAME="${{ github.ref_name }}"
           if [ "$BRANCH_NAME" = "main" ]; then
             OVERLAY="prod"
           elif [ "$BRANCH_NAME" = "develop" ]; then