Fully implement Kavenegar SMS support

Core changes:
- ISmsService: add SendBulkAsync (batches of 200) + GetAccountInfoAsync
- KavenegarSmsService: POST requests, sender number config, bulk send
  via comma-separated receptors, account balance, full error code mapping
  (HTTP 400-432), enabled-flag check before any send
- SmsMarketingService: replaced per-recipient loop with SendBulkAsync
- SmsController: new GET /sms/balance endpoint returns Kavenegar credit
- SmsDtos: SmsBalanceDto
- IntegrationDtos + PlatformIntegrationService: SenderNumber field
- appsettings.json + docker-compose: Kavenegar__SenderNumber = 90005671

Dashboard:
- sms-screen: char counter, SMS parts indicator (Persian 70/67 chars,
  Latin 160/153), account balance card, sender line display, result banner

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Meezi.API/Controllers/SmsController.cs

@@ -11,16 +11,32 @@ namespace Meezi.API.Controllers;
 public class SmsController : CafeApiControllerBase
 {
     private readonly ISmsMarketingService _smsMarketingService;
+    private readonly ISmsService _smsService;
     private readonly IValidator<SendSmsCampaignRequest> _campaignValidator;
 
     public SmsController(
         ISmsMarketingService smsMarketingService,
+        ISmsService smsService,
         IValidator<SendSmsCampaignRequest> campaignValidator)
     {
         _smsMarketingService = smsMarketingService;
+        _smsService = smsService;
         _campaignValidator = campaignValidator;
     }
 
+    [HttpGet("balance")]
+    public async Task<IActionResult> GetBalance(string cafeId, ITenantContext tenant, CancellationToken cancellationToken)
+    {
+        if (EnsureCafeAccess(cafeId, tenant) is { } denied) return denied;
+
+        var info = await _smsService.GetAccountInfoAsync(cancellationToken);
+        var dto = info is not null
+            ? new SmsBalanceDto(info.RemainCredit, info.AccountType, true)
+            : new SmsBalanceDto(0, "master", false);
+
+        return Ok(new ApiResponse<SmsBalanceDto>(true, dto));
+    }
+
     [HttpGet("usage")]
     public async Task<IActionResult> GetUsage(string cafeId, ITenantContext tenant, CancellationToken cancellationToken)
     {

src/Meezi.API/Models/Crm/SmsDtos.cs

@@ -10,3 +10,6 @@ public record SendSmsCampaignRequest(
 public record SmsCampaignResult(int SentCount, int FailedCount);
 
 public record SmsUsageDto(int UsedThisMonth, int MonthlyLimit, string Month);
+
+/// <summary>Kavenegar account credit balance returned to the dashboard.</summary>
+public record SmsBalanceDto(long RemainCredit, string AccountType, bool IsConfigured);

src/Meezi.API/Services/SmsMarketingService.cs

@@ -24,18 +24,15 @@ public class SmsMarketingService : ISmsMarketingService
     private readonly AppDbContext _db;
     private readonly ISmsService _smsService;
     private readonly IConnectionMultiplexer _redis;
-    private readonly ILogger<SmsMarketingService> _logger;
 
     public SmsMarketingService(
         AppDbContext db,
         ISmsService smsService,
-        IConnectionMultiplexer redis,
-        ILogger<SmsMarketingService> logger)
+        IConnectionMultiplexer redis)
     {
         _db = db;
         _smsService = smsService;
         _redis = redis;
-        _logger = logger;
     }
 
     public async Task<SmsUsageDto> GetUsageAsync(
@@ -68,27 +65,12 @@ public class SmsMarketingService : ISmsMarketingService
         if (maxSms != int.MaxValue && used + phones.Count > maxSms)
             return (false, null, "PLAN_LIMIT_REACHED", "Monthly SMS limit would be exceeded.");
 
-        var sent = 0;
-        var failed = 0;
+        var result = await _smsService.SendBulkAsync(phones, request.Message, cancellationToken);
 
-        foreach (var phone in phones)
-        {
-            try
-            {
-                await _smsService.SendMessageAsync(phone, request.Message, cancellationToken);
-                sent++;
-            }
-            catch (Exception ex)
-            {
-                _logger.LogWarning(ex, "Failed to send SMS to recipient");
-                failed++;
-            }
-        }
+        if (result.SentCount > 0)
+            await IncrementUsageAsync(cafeId, month, result.SentCount);
 
-        if (sent > 0)
-            await IncrementUsageAsync(cafeId, month, sent);
-
-        return (true, new SmsCampaignResult(sent, failed), null, null);
+        return (true, new SmsCampaignResult(result.SentCount, result.FailedCount), null, null);
     }
 
     private async Task<List<string>> ResolvePhonesAsync(

src/Meezi.API/appsettings.json

@@ -37,6 +37,7 @@
   },
   "Kavenegar": {
     "ApiKey": "",
+    "SenderNumber": "90005671",
     "OtpTemplate": "verify"
   },
   "ZarinPal": {