fix(mana-sync): update Dockerfile to copy workspace shared-go dependency

The Dockerfile only copied services/mana-sync, but go.mod has a replace
directive pointing to ../../packages/shared-go which needs to be in the
build context. Switch context to repo root and copy both packages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.macmini.yml

@@ -535,8 +535,8 @@ services:
 
   mana-sync:
     build:
-      context: services/mana-sync
-      dockerfile: Dockerfile
+      context: .
+      dockerfile: services/mana-sync/Dockerfile
     image: mana-sync:local
     container_name: mana-core-sync
     restart: always