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.

tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Audit/AuditGridColumnTests.cs

@@ -30,7 +30,7 @@ public class AuditGridColumnTests
     /// <summary>Skip reason shared by the DB-seeding tests when MSSQL is down.</summary>
     private const string DbUnavailableSkipReason =
         "AuditDataSeeder cannot reach MSSQL at localhost:1433 — bring up infra/docker-compose and docker/deploy.sh, " +
-        "or set SCADALINK_PLAYWRIGHT_DB to a reachable connection string.";
+        "or set SCADABRIDGE_PLAYWRIGHT_DB to a reachable connection string.";
 
     private readonly PlaywrightFixture _fixture;