Reorganize project structure for nested Visual Studio solution

- Moved src, tests, docs, scripts, config, and solution-filters into ShadowedRealmsMobile/ directory
- Created nested structure to align with Visual Studio Blank Solution layout
- Maintains clean separation between repository metadata and solution files
- Ready for Visual Studio project creation within nested structure

ShadowedRealmsMobile/ShadowedRealmsMobile.sln

@@ -0,0 +1,13 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.14.36603.0 d17.14
+MinimumVisualStudioVersion = 10.0.40219.1
+Global
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {C47922C3-662D-44B2-A7FA-8F30AF7B34C5}
+	EndGlobalSection
+EndGlobal