feat: Set up initial WebClientTpos .NET project structure, including client, server, assets, and documentation.

apps/web-client-tpos-net/src/WebClientTpos.Client/Localization/LocalizationCache.cs

@@ -0,0 +1,50 @@
+using System.Globalization;
+using System.Net.Http.Json;
+
+namespace WebClientTpos.Client.Localization;
+
+public class LocalizationCache
+{
+    private readonly HttpClient _httpClient;
+    private Dictionary<string, string> _strings = new();
+    private bool _isLoaded;
+
+    public LocalizationCache(HttpClient httpClient)
+    {
+        _httpClient = httpClient;
+    }
+
+    public string? GetString(string key)
+    {
+        if (_strings.TryGetValue(key, out var value))
+        {
+            return value;
+        }
+        return null;
+    }
+
+    public async Task LoadAsync(CultureInfo culture)
+    {
+        if (_isLoaded) return; // Or check if culture changed
+
+        try
+        {
+            var cultureName = culture.Name;
+            // Map generic "vi" to "vi-VN" if needed, but for now we trust the culture name matches file
+            // Fallback for simple "vi" -> "vi-VN"
+            if (cultureName == "vi") cultureName = "vi-VN";
+            if (cultureName == "en") cultureName = "en-US";
+
+            var loaded = await _httpClient.GetFromJsonAsync<Dictionary<string, string>>($"/locales/{cultureName}.json?v={DateTime.Now.Ticks}");
+            if (loaded != null)
+            {
+                _strings = loaded;
+                _isLoaded = true;
+            }
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Error loading localization for {culture.Name}: {ex.Message}");
+        }
+    }
+}