Use host runners instead of Docker containers

Simplified runner configuration to use host execution instead of Docker-in-Docker for better performance.

Configure runners with:
- Raspberry Pi: linux-arm64:host
- Laptop: linux-amd64:host

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

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

.gitea/workflows/build.yml

@@ -48,8 +48,10 @@ jobs:
         include:
           - platform: linux/amd64
             runner: linux-amd64
+            arch: amd64
           - platform: linux/arm64
             runner: linux-arm64
+            arch: arm64
     runs-on: ${{ matrix.runner }}
     steps:
       - name: Checkout code