refactor: scrub residual ScadaLink refs → ScadaBridge (env vars, config keys, assembly name, SQL login)

Renames the 13 SCADALINK_* runtime env vars → SCADABRIDGE_*, the ScadaLink__
.NET config keys → ScadaBridge__, the stale ScadaLink.Host.exe assembly name
→ ZB.MOM.WW.ScadaBridge.Host.exe, the scadalink_app SQL login → scadabridge_app,
and residual identifiers/comments/docs. Migration records (prior rename
tooling/design, DB-rename helper, this scrub script) carved out.

Adds tools/scrub-scadalink-refs.sh.

docker-env2/docker-compose.yml

@@ -3,7 +3,7 @@ services:
     image: scadabridge:latest
     container_name: scadabridge-env2-central-a
     environment:
-      SCADALINK_CONFIG: Central
+      SCADABRIDGE_CONFIG: Central
       ASPNETCORE_ENVIRONMENT: Development
       ASPNETCORE_URLS: "http://+:5000"
     ports:
@@ -20,7 +20,7 @@ services:
     image: scadabridge:latest
     container_name: scadabridge-env2-central-b
     environment:
-      SCADALINK_CONFIG: Central
+      SCADABRIDGE_CONFIG: Central
       ASPNETCORE_ENVIRONMENT: Development
       ASPNETCORE_URLS: "http://+:5000"
     ports:
@@ -37,7 +37,7 @@ services:
     image: scadabridge:latest
     container_name: scadabridge-env2-site-x-a
     environment:
-      SCADALINK_CONFIG: Site
+      SCADABRIDGE_CONFIG: Site
     ports:
       - "9121:8082"   # Akka remoting
       - "9123:8083"   # gRPC streaming
@@ -53,7 +53,7 @@ services:
     image: scadabridge:latest
     container_name: scadabridge-env2-site-x-b
     environment:
-      SCADALINK_CONFIG: Site
+      SCADABRIDGE_CONFIG: Site
     ports:
       - "9122:8082"   # Akka remoting
       - "9124:8083"   # gRPC streaming