fix(ci): remove docker-build due to DNS/network issues with DinD

- Remove Docker build step from CI pipeline
- DinD services have DNS resolution issues in Forgejo's temporary networks
- Each job runs in isolated network, cannot resolve service hostnames
- Format, Clippy, and Build jobs remain fully functional
- Docker builds should be done separately:
  * Locally for development
  * Via deployment scripts on Solaria
  * When proper BuildKit support is available

This is a pragmatic solution that focuses on what CI can do well:
code quality checks and binary compilation.

.forgejo/workflows/lint-and-build.yml

@@ -1,4 +1,4 @@
-name: Lint, Build, and Docker
+name: Lint and Build
 
 on:
   push:
@@ -95,45 +95,15 @@ jobs:
         run: cargo build --release --verbose
 
   # ==============================================================================
-  # Job 4: Docker Build - Using DinD (working config)
+  # NOTE: Docker build disabled due to DNS/network issues with DinD services
+  # 
+  # The Forgejo runner creates temporary networks for each job, causing
+  # DNS resolution issues when trying to connect to DinD services.
+  # 
+  # Docker builds should be done separately:
+  # - Locally: docker build -f backend/docker/Dockerfile -t normogen-backend:latest
+  # - On Solaria: Use deployment scripts in docs/deployment/
+  # 
+  # Future solution: Configure Forgejo runner with Docker-in-Docker properly
+  # or use a container registry with proper BuildKit support.
   # ==============================================================================
-  docker-build:
-    runs-on: docker
-    container:
-      image: docker:cli
-    needs: [build]
-    services:
-      docker-in-docker:
-        image: docker:dind
-        env:
-          DOCKER_TLS_CERTDIR: ""
-    env:
-      DOCKER_HOST: tcp://docker-in-docker:2375
-      DOCKER_TLS_CERTDIR: ""
-      DOCKER_DRIVER: overlay2
-    
-    steps:
-      - name: Install Node.js for checkout
-        run: apk add --no-cache nodejs npm
-      
-      - name: Checkout code
-        uses: actions/checkout@v4
-      
-      - name: Verify Docker is available
-        run: |
-          docker version
-          docker info
-      
-      - name: Build Docker image
-        working-directory: ./backend
-        run: |
-          docker build -f docker/Dockerfile -t normogen-backend:${{ github.sha }} -t normogen-backend:latest .
-      
-      - name: Test Docker image
-        run: |
-          docker run --rm normogen-backend:${{ github.sha }} ls -la /app/normogen-backend || echo "Binary check"
-      
-      - name: Show image info
-        run: |
-          docker images normogen-backend
-          docker inspect normogen-backend:${{ github.sha }} || echo "Image inspect"