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.

src/ZB.MOM.WW.ScadaBridge.Host/Properties/launchSettings.json

@@ -9,7 +9,7 @@
       "environmentVariables": {
         "DOTNET_ENVIRONMENT": "Development",
         "ASPNETCORE_ENVIRONMENT": "Development",
-        "SCADALINK_CONFIG": "Central"
+        "SCADABRIDGE_CONFIG": "Central"
       }
     },
     "ScadaBridge Site": {
@@ -19,7 +19,7 @@
       "environmentVariables": {
         "DOTNET_ENVIRONMENT": "Development",
         "ASPNETCORE_ENVIRONMENT": "Development",
-        "SCADALINK_CONFIG": "Site"
+        "SCADABRIDGE_CONFIG": "Site"
       }
     }
   }