fix: bust Docker cache for tools that fetch latest versions

The native Claude Code installer (and other tools) fetch "latest" at
build time, but Docker layer caching serves stale layers because the
RUN command text never changes. Add TOOLS_CACHEBUST build arg with
github.run_id so every CI run re-downloads fresh tool binaries.

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

.github/workflows/build-and-push.yaml

@@ -57,6 +57,8 @@ jobs:
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            TOOLS_CACHEBUST=${{ github.run_id }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
           platforms: linux/amd64

.github/workflows/release-unified.yaml

@@ -100,6 +100,8 @@ jobs:
             ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.version.outputs.tag }}
             ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.version.outputs.version }}
             ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
+          build-args: |
+            TOOLS_CACHEBUST=${{ github.run_id }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
           platforms: linux/amd64