Harden admin telemetry and deployment safeguards

TaxBaik.Web/Program.cs

@@ -7,10 +7,12 @@ using Microsoft.AspNetCore.Authentication.Cookies;
 using Microsoft.AspNetCore.Authentication.OAuth;
 using Microsoft.AspNetCore.Components.Authorization;
 using Microsoft.AspNetCore.HttpOverrides;
+using Microsoft.AspNetCore.RateLimiting;
 using Microsoft.AspNetCore.ResponseCompression;
 using Microsoft.IdentityModel.Tokens;
 using MudBlazor.Services;
 using Serilog;
+using System.Threading.RateLimiting;
 using TaxBaik.Application;
 using TaxBaik.Application.Services;
 using TaxBaik.Infrastructure;
@@ -51,6 +53,23 @@ builder.Host.UseSerilog((context, config) =>
 builder.Services.AddControllers();
 builder.Services.AddProblemDetails();
 builder.Services.AddHealthChecks();
+builder.Services.AddRateLimiter(options =>
+{
+    options.RejectionStatusCode = StatusCodes.Status429TooManyRequests;
+    options.AddPolicy("client-logs", httpContext =>
+    {
+        var ip = httpContext.Connection.RemoteIpAddress?.ToString() ?? "unknown";
+        return RateLimitPartition.GetFixedWindowLimiter(
+            partitionKey: $"client-logs:{ip}",
+            factory: _ => new FixedWindowRateLimiterOptions
+            {
+                PermitLimit = 10,
+                Window = TimeSpan.FromMinutes(1),
+                QueueLimit = 0,
+                AutoReplenishment = true
+            });
+    });
+});
 
 // Razor Pages + Blazor Server 통합
 builder.Services.AddRazorPages();
@@ -351,6 +370,7 @@ app.UsePathBase("/taxbaik");
 app.UseResponseCompression();
 app.UseStaticFiles();
 app.UseRouting();
+app.UseRateLimiter();
 app.UseAuthentication();
 app.UseAuthorization();
 app.UseAntiforgery();
@@ -387,12 +407,14 @@ catch (Exception ex)
     {
         try
         {
-            using (var scope = app.Services.CreateScope())
+            var fatalMessage = $"환경: {app.Environment.EnvironmentName}\n오류: {ex.Message}";
+            if (TaxBaik.Web.Services.TelegramAlertGate.ShouldSend("telegram:fatal", fatalMessage, TimeSpan.FromMinutes(30)))
             {
+                using var scope = app.Services.CreateScope();
                 var telegramService = scope.ServiceProvider.GetRequiredService<ITelegramNotificationService>();
                 await telegramService.SendErrorAsync(
                     "❌ 서버 오류",
-                    $"환경: {app.Environment.EnvironmentName}\n오류: {ex.Message}");
+                    fatalMessage);
             }
         }
         catch (Exception telegramEx)