v1.3.0 Restructure Saxonite workspace and upgrade to .NET 10 (#1)

Move Saxonite’s projects into a dedicated `Workspace` folder and align the solution with .NET 10 and the current Common workspace. Update encryption integration, test project structure and coverage, and repository guidance and upgrade notes.

- Relocate application and library projects while retaining Git rename history.
- Split tests into Admin, Online, and Shared projects; add representative behavioral and serialization tests.
- Update Common integration, application version, and repository documentation.

Application version: 1.3.0

Reviewed-on: #1
Co-authored-by: andy <andy@sarand.com>

.gitignore

@@ -360,4 +360,17 @@ MigrationBackup/
 .ionide/
 
 # Fody - auto-generated XML schema
-FodyWeavers.xsd
+FodyWeavers.xsd
+
+# Generated deployment archives and shortcuts
+/Deploy/Generated/
+
+# Generated database source snapshots
+/Database/Generated/
+
+# NuGet cache metadata and local source shortcuts
+**/.nupkg.metadata
+**/.signature.p7s
+**/*.nupkg.sha512
+**/*.lnk
+**/*.url