fix: Build only linux/amd64 to avoid QEMU emulation failures

ARM64 builds were failing with 'Illegal instruction' errors during npm ci
due to QEMU emulation issues. Since PatchMon is a Node.js application,
AMD64 images will run fine on ARM64 systems (like Apple Silicon Macs)
using Rosetta emulation. This simplifies the build process.

.github/workflows/docker.yml

@@ -64,7 +64,7 @@ jobs:
         with:
           context: .
           file: docker/${{ matrix.image }}.Dockerfile
-          platforms: linux/amd64,linux/arm64
+          platforms: linux/amd64
           # Push if:
           # - Event is not workflow_dispatch OR input 'push' is true
           # AND