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.Transport.Tests/Serialization/BundleSerializerTests.cs

@@ -28,7 +28,7 @@ public sealed class BundleSerializerTests
         new ManifestBuilder().Build(
             sourceEnvironment: "test-env",
             exportedBy: "tester",
-            scadaLinkVersion: "1.0.0",
+            scadaBridgeVersion: "1.0.0",
             encryption: encryption,
             summary: new BundleSummary(0, 1, 1, 0, 0, 0, 0, 0, 0),
             contents: Array.Empty<ManifestContentEntry>(),