docs: complete XML doc coverage (returns, summaries, inheritdoc)

Resolve all 622 issues flagged by the enhanced CommentChecker: add missing
<returns> tags (incl. the standard phrasing on non-generic Task methods),
add missing <summary> tags, and replace misused/redundant <inheritdoc/> on
members that override or implement nothing with real documentation.
Documentation-only — no behavior change; solution builds clean.

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/DesignTimeDbContextFactory.cs

@@ -26,6 +26,7 @@ public class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<ScadaBridg
     /// Creates a <see cref="ScadaBridgeDbContext"/> for design-time EF Core tooling.
     /// </summary>
     /// <param name="args">Arguments passed by the EF tooling (unused).</param>
+    /// <returns>A configured <see cref="ScadaBridgeDbContext"/> pointing at the resolved connection string.</returns>
     public ScadaBridgeDbContext CreateDbContext(string[] args)
     {
         var configurationBuilder = new ConfigurationBuilder();