feat(centralui): rebrand web UI to ScadaBridge + technical-light theme

Rename the user-facing product name from ScadaLink to ScadaBridge across
the six display strings (browser title, sidebar brand, login + not-authorized
headings, dashboard welcome/subtitle). Namespaces, assemblies, config keys,
and _content/ScadaLink.CentralUI asset routes are unchanged.

Apply the technical-light design system: vendor theme.css + IBM Plex fonts
into the CentralUI RCL, include theme.css globally (after Bootstrap so its
--bs-* token overrides win), and restyle the layout chrome to a light
sidebar — white surface, hairline rules, ink text, accent-blue active item,
the brand accent mark. Page markup stays Bootstrap and inherits the warm
paper background, Plex type, accent, and hairline borders via the tokens.

Tests: build 0 warnings; bUnit 542 passed; Playwright 64 passed.

tests/ScadaLink.CentralUI.Tests/ComponentRenderingTests.cs

@@ -73,11 +73,11 @@ public class ComponentRenderingTests : BunitContext
     }
 
     [Fact]
-    public void LoginPage_RendersScadaLinkTitle()
+    public void LoginPage_RendersScadaBridgeTitle()
     {
         var cut = Render<Login>();
 
         var title = cut.Find("h4.card-title");
-        Assert.Equal("ScadaLink", title.TextContent);
+        Assert.Equal("ScadaBridge", title.TextContent);
     }
 }