Use host app's base directory for InstallPath default

Changed default InstallPath from %APPDATA%/~/.config to AppDomain.CurrentDomain.BaseDirectory. This:
- Extracts path from host program's runtime location
- Requires no admin privileges (uses app's own directory)
- Aligns with existing codebase pattern (Thread.GetDomain().BaseDirectory)
- More universal and highly available across deployments

Co-authored-by: JusterZhu <11714536+JusterZhu@users.noreply.github.com>

Author: Copilot

src/c#/CoreTest/Shared/ConfiginfoBuilderTests.cs

@@ -140,18 +140,18 @@ public void Build_GeneratesPlatformSpecificDefaults()
             // Assert
             Assert.NotNull(config.InstallPath);
 
+            // InstallPath should be the current application's base directory
+            Assert.Equal(AppDomain.CurrentDomain.BaseDirectory, config.InstallPath);
+            
             if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
                 // Windows-specific assertions
                 Assert.Contains("App.exe", config.AppName);
-                Assert.Contains("GeneralUpdate", config.InstallPath);
             }
             else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
             {
                 // Linux-specific assertions
                 Assert.DoesNotContain(".exe", config.AppName);
-                Assert.Contains(".config", config.InstallPath);
-                Assert.Contains("GeneralUpdate", config.InstallPath);
             }
         }
 
@@ -531,7 +531,8 @@ public void Build_OnWindows_GeneratesWindowsDefaults()
 
             // Assert
             Assert.Contains("App.exe", config.AppName);
-            Assert.Contains("GeneralUpdate", config.InstallPath);
+            // Should use the current application's base directory
+            Assert.Equal(AppDomain.CurrentDomain.BaseDirectory, config.InstallPath);
             // Windows script should be empty
             Assert.Empty(config.Script);
         }
@@ -556,8 +557,8 @@ public void Build_OnLinux_GeneratesLinuxDefaults()
 
             // Assert
             Assert.DoesNotContain(".exe", config.AppName);
-            Assert.Contains(".config", config.InstallPath);
-            Assert.Contains("GeneralUpdate", config.InstallPath);
+            // Should use the current application's base directory
+            Assert.Equal(AppDomain.CurrentDomain.BaseDirectory, config.InstallPath);
             // Linux should have a default permission script
             Assert.NotEmpty(config.Script);
             Assert.Contains("chmod", config.Script);

src/c#/GeneralUpdate.Common/Shared/Object/ConfiginfoBuilder-Usage.md

@@ -26,19 +26,21 @@ var config = new ConfiginfoBuilder(
 The builder automatically detects the runtime platform and sets appropriate defaults:
 
 ### Windows Platform
-- **Install Path**: `%APPDATA%\GeneralUpdate`
+- **Install Path**: Current application's base directory (via `AppDomain.CurrentDomain.BaseDirectory`)
 - **App Names**: Uses `.exe` extension (e.g., `App.exe`)
 - **Script**: Empty (Windows doesn't typically need permission scripts)
 - **Path Separator**: Backslash (`\`) - handled automatically by .NET
 - **Black Formats**: `.log`, `.tmp` (from `ConfiginfoBuilder.DefaultBlackFormats`)
 
 ### Linux Platform
-- **Install Path**: `~/.config/GeneralUpdate`
+- **Install Path**: Current application's base directory (via `AppDomain.CurrentDomain.BaseDirectory`)
 - **App Names**: No `.exe` extension (e.g., `app`)
 - **Script**: Default chmod script for granting execution permissions
 - **Path Separator**: Forward slash (`/`) - handled automatically by .NET
 - **Black Formats**: `.log`, `.tmp` (from `ConfiginfoBuilder.DefaultBlackFormats`)
 
+**Note**: The install path defaults to the current application's running directory, which does not require administrator privileges and automatically extracts the location from the host program.
+
 ## Customizing Configuration
 
 You can override any default value using the fluent API:
@@ -252,12 +254,12 @@ var config = new ConfiginfoBuilder(updateUrl, token, scheme).Build();
 if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
 {
     Console.WriteLine($"Windows config: {config.InstallPath}");
-    // Output: Windows config: C:\Users\Username\AppData\Roaming\GeneralUpdate
+    // Output: Windows config: C:\MyApp\ (current application directory)
 }
 else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
 {
     Console.WriteLine($"Linux config: {config.InstallPath}");
-    // Output: Linux config: /home/username/.config/GeneralUpdate
+    // Output: Linux config: /opt/myapp/ (current application directory)
 }
 ```
 

src/c#/GeneralUpdate.Common/Shared/Object/ConfiginfoBuilder.cs

@@ -98,9 +98,9 @@ private void InitializePlatformDefaults()
         /// </summary>
         private void InitializeWindowsDefaults()
         {
-            // Use APPDATA for configuration storage on Windows
-            var appDataPath = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
-            _installPath = Path.Combine(appDataPath, "GeneralUpdate");
+            // Use the current application's base directory (no admin privileges required)
+            // This extracts the path from the host program's runtime location
+            _installPath = AppDomain.CurrentDomain.BaseDirectory;
 
             // Windows uses backslash as path separator (handled automatically by Path.Combine)
             // Set Windows-specific executable names
@@ -116,10 +116,9 @@ private void InitializeWindowsDefaults()
         /// </summary>
         private void InitializeLinuxDefaults()
         {
-            // Use ~/.config for configuration storage on Linux (XDG Base Directory Specification)
-            var homeDirectory = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
-            var configPath = Path.Combine(homeDirectory, ".config");
-            _installPath = Path.Combine(configPath, "GeneralUpdate");
+            // Use the current application's base directory (no admin privileges required)
+            // This extracts the path from the host program's runtime location
+            _installPath = AppDomain.CurrentDomain.BaseDirectory;
 
             // Linux uses forward slash as path separator (handled automatically by Path.Combine)
             // Linux executables typically don't have .exe extension

src/c#/GeneralUpdate.Common/Shared/Object/README-ConfiginfoBuilder.md

@@ -34,7 +34,7 @@ The builder automatically adapts based on your runtime environment:
 
 | Aspect | Windows | Linux |
 |--------|---------|-------|
-| Install Path | `%APPDATA%\GeneralUpdate` | `~/.config/GeneralUpdate` |
+| Install Path | Current app directory | Current app directory |
 | App Names | `App.exe` | `app` |
 | Script | Empty | chmod script |
 | Path Separator | `\` (automatic) | `/` (automatic) |