fix: use platform-specific packages for Docker builds (linux-x64, linux-arm64)

- Map Docker platform format (linux/amd64, linux/arm64) to Nuke platform format (linux-x64, linux-arm64)
- Download platform-specific packages instead of generic package
- For multi-arch builds, download both linux-x64 and linux-arm64 packages
- Merge both package lib directories for multi-arch builds
- Remove redundant copy command since packages are now handled correctly
- Include -nort suffix in package name (framework-dependent packages)
- Fix bash variable expansion in echo statements (remove single quotes around ${CLEAN_VERSION})
- Add platform input to repository_dispatch trigger for explicit platform control

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: newbe36524

.github/workflows/docker-build.yml

@@ -50,6 +50,15 @@ on:
       version:
         description: 'Version to build (passed from version monitor)'
         required: false
+      platform:
+        description: 'Docker platform (all, linux-amd64, linux-arm64)'
+        required: false
+        type: choice
+        default: all
+        options:
+          - all
+          - linux-amd64
+          - linux-arm64
 
 permissions:
   contents: write  # Required for uploading release assets