Refactor annotation tool from WPF desktop app to .NET API

Replace the WPF desktop application (Azaion.Suite, Azaion.Annotator,
Azaion.Common, Azaion.Inference, Azaion.Loader, Azaion.LoaderUI,
Azaion.Dataset, Azaion.Test) with a standalone .NET Web API in src/.

Made-with: Cursor

.gitignore

@@ -1,3 +1,4 @@
+.DS_Store
 .idea
 bin
 obj
@@ -9,17 +10,29 @@ obj
 *.user
 log*.txt
 secured-config
-build
 venv
 *.c
 *.pyd
 cython_debug*
-dist-dlls
-dist-azaion
-Azaion*.exe
-Azaion*.bin
 
 azaion\.*\.big
 _internal
 dist
 *.jpg
+
+.env
+docker-compose.override.yml
+
+# AI Training credentials
+ai-training/config.yaml
+ai-training/cdn.yaml
+ai-training/offset.yaml
+ai-training/_other/
+
+# UI
+ui/node_modules
+ui/dist
+
+*.enc
+key-fragment*.bin
+images.tar