perf(ci): switch docker builds to registry cache

Replace GHA cache (Blacksmith-proxied, flaky 502s) with GHCR registry
cache. Benchmarked at 2x faster on both cold and warm builds.

Author: izadoesdev

.github/workflows/docker-publish.yml

@@ -163,8 +163,8 @@ jobs:
             VERSION=${{ steps.version.outputs.tag }}
             BUILD_DATE=${{ steps.builddate.outputs.timestamp }}
             GIT_SHA=${{ github.sha }}
-          cache-from: type=gha,scope=${{ matrix.service }}-${{ matrix.platform.arch }}
-          cache-to: type=gha,mode=max,scope=${{ matrix.service }}-${{ matrix.platform.arch }}
+          cache-from: type=registry,ref=${{ env.IMAGE_PREFIX }}-${{ matrix.service }}:cache-${{ matrix.platform.arch }}
+          cache-to: type=registry,ref=${{ env.IMAGE_PREFIX }}-${{ matrix.service }}:cache-${{ matrix.platform.arch }},mode=max
 
       - name: Scan image for vulnerabilities
         if: always() && steps.build.outcome != 'cancelled'