Bump to v2.0.0: blue theme upgrade demo

Changes version to 2.0.0 and header color from teal (#0F766E) to blue (#1D4ED8).
Used to demonstrate a zero-data-loss upgrade on Clouderized.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/main/resources/site.conf

@@ -1,8 +1,8 @@
 app {
   name = "DemoCust Tasks"
-  version = "1.0.0"
+  version = "2.0.0"
   theme {
-    background = "#0F766E"
+    background = "#1D4ED8"
     font = "DM Sans"
     fontSize = "16px"
   }