Relocate app data and package build output

Adds a new `AppPaths` helper and moves runtime/user-generated files (`init.config`, `custom_set.txt`, cache, WebView2 data) into `%LocalAppData%\Lithium` with readable fallback to portable files. WebView2 initialization now sets a loader DLL path, uses an explicit user data folder, and surfaces runtime-missing errors.

The build/publish pipeline is updated to emit a clean `Build\` layout with dependencies under `lib\`, remove duplicate root DLL/docs, and align probing/runtime settings for net48 x64 output. Supporting updates include ignore rules for build/runtime artifacts, refreshed agent build/release docs, and endpoint URL/domain updates.

Lithium/ConfigLoader.cs

@@ -72,9 +72,10 @@ namespace Lua
             SetConsoleColor();
 
             // AA0019
-            if (!File.Exists("init.config")) return;
+            string configPath = AppPaths.GetReadableFilePath("init.config");
+            if (configPath == null) return;
 
-            var lines = Helper.ReadLinesSafe("init.config");
+            var lines = Helper.ReadLinesSafe(configPath);
 
             // AA0020
             foreach (var raw in lines)