feat: implement Telegram multi-channel logging and enhance admin UI/UX guidelines

Telegram Logging Enhancements:
- Support multi-channel notifications (inquiry: -5434691215, system: -5585148480)
- New methods: SendInquiryNotificationAsync, SendSystemNotificationAsync
- Dynamic chat ID routing based on notification type
- Backward compatible with existing default ChatId configuration

Admin UI/UX Improvements (CLAUDE.md 10.5):
- Enter key focus transition between form fields
- Auto-submit on last field (with validation)
- Tab key equivalent with explicit input intent
- Applied to all admin management pages

Dorsum ERP Integration Guide (CLAUDE.md 10.6):
- Clear role definition: Dorsum (tax processing) vs TaxBaik (CRM/customer management)
- Elimination of data duplication principles
- Unique TaxBaik features (contract tracking, revenue management, CRM activities)
- Data ownership matrix (who owns what data)
- Future Dorsum API sync strategy (webhook/polling)

Guidelines Updates:
- Form field Enter key handling pattern
- Multi-tenant company management alignment
- API-first architecture reinforcement

Build Status: ✅ Success (0 errors, 3 warnings)

TaxBaik.Web/Services/TelegramNotificationService.cs

@@ -11,6 +11,8 @@ public interface ITelegramNotificationService
     Task SendMessageAsync(string message, CancellationToken ct = default);
     Task SendErrorAsync(string title, string details, CancellationToken ct = default);
     Task SendInfoAsync(string title, string message, CancellationToken ct = default);
+    Task SendInquiryNotificationAsync(string message, CancellationToken ct = default);
+    Task SendSystemNotificationAsync(string message, CancellationToken ct = default);
 }
 
 public class TelegramNotificationService : ITelegramNotificationService
@@ -18,7 +20,9 @@ public class TelegramNotificationService : ITelegramNotificationService
     private readonly HttpClient _httpClient;
     private readonly ILogger<TelegramNotificationService> _logger;
     private readonly string _botToken;
-    private readonly string _chatId;
+    private readonly string _defaultChatId;
+    private readonly string _inquiryChatId;
+    private readonly string _systemChatId;
     private const string TelegramApiUrl = "https://api.telegram.org";
 
     public TelegramNotificationService(
@@ -29,23 +33,42 @@ public class TelegramNotificationService : ITelegramNotificationService
         _httpClient = httpClient;
         _logger = logger;
         _botToken = config["Telegram:BotToken"] ?? "";
-        _chatId = config["Telegram:ChatId"] ?? "";
+        _defaultChatId = config["Telegram:ChatId"] ?? "";
+        _inquiryChatId = config["Telegram:InquiryChatId"] ?? "-5434691215";
+        _systemChatId = config["Telegram:SystemChatId"] ?? "-5585148480";
     }
 
     public async Task SendMessageAsync(string message, CancellationToken ct = default)
     {
-        if (string.IsNullOrEmpty(_botToken) || string.IsNullOrEmpty(_chatId))
+        if (string.IsNullOrEmpty(_botToken) || string.IsNullOrEmpty(_defaultChatId))
         {
             _logger.LogWarning("Telegram credentials not configured");
             return;
         }
 
+        await SendToChat(_defaultChatId, message, ct);
+    }
+
+    public async Task SendInquiryNotificationAsync(string message, CancellationToken ct = default) =>
+        await SendToChat(_inquiryChatId, $"<b>📋 문의 사항</b>\n\n{message}", ct);
+
+    public async Task SendSystemNotificationAsync(string message, CancellationToken ct = default) =>
+        await SendToChat(_systemChatId, $"<b>🔧 시스템 알림</b>\n\n{message}", ct);
+
+    private async Task SendToChat(string chatId, string message, CancellationToken ct)
+    {
+        if (string.IsNullOrEmpty(_botToken) || string.IsNullOrEmpty(chatId))
+        {
+            _logger.LogWarning("Telegram credentials not configured for chatId {ChatId}", chatId);
+            return;
+        }
+
         try
         {
             var url = $"{TelegramApiUrl}/bot{_botToken}/sendMessage";
             var payload = new
             {
-                chat_id = _chatId,
+                chat_id = chatId,
                 text = message,
                 parse_mode = "HTML"
             };
@@ -53,12 +76,12 @@ public class TelegramNotificationService : ITelegramNotificationService
             var response = await _httpClient.PostAsJsonAsync(url, payload, cancellationToken: ct);
             if (!response.IsSuccessStatusCode)
             {
-                _logger.LogError("Failed to send Telegram message: {StatusCode}", response.StatusCode);
+                _logger.LogError("Failed to send Telegram message to {ChatId}: {StatusCode}", chatId, response.StatusCode);
             }
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "Error sending Telegram message");
+            _logger.LogError(ex, "Error sending Telegram message to {ChatId}", chatId);
         }
     }