fix: sidebar accordion + koja slug + support ticket LINQ crash

Sidebar:
- All groups start collapsed on first load (v4 storage key resets old state)
- Opening one group closes all others (accordion)
- Navigating to a section opens only that section's group

Koja slug:
- SlugHelper: Persian->Latin transliteration, slug validation
- Registration accepts optional custom slug; auto-derives from cafe name
- Slug can be updated from dashboard Settings -> Profile
- Settings PATCH validates uniqueness (SLUG_TAKEN) and format (INVALID_SLUG)
- koja.meezi.ir/{slug} now redirects to /fa/cafe/{slug} (short URL support)

Bug fix:
- SupportTicketService: cafeId/status filters applied before Select() projection
  to fix EF "could not be translated" crash on the support tickets page

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

src/Meezi.API/Services/AuthService.cs

@@ -303,8 +303,15 @@ public class AuthService : IAuthService
 
         var otp = Random.Shared.Next(100000, 999999).ToString();
         await redis.StringSetAsync($"otp:{phone}", otp, TimeSpan.FromSeconds(OtpTtlSeconds));
-        // Store the cafe name alongside the OTP so verify-register can create the cafe
-        await redis.StringSetAsync($"reg_meta:{phone}", cafeName, TimeSpan.FromSeconds(OtpTtlSeconds));
+
+        // Determine the requested slug: use provided slug, or auto-derive from café name.
+        // Format stored: "cafeName||slug" (double-pipe delimiter). Slug may be empty.
+        var requestedSlug = string.IsNullOrWhiteSpace(request.Slug)
+            ? Meezi.Core.Utilities.SlugHelper.Slugify(cafeName)
+            : request.Slug.Trim().ToLowerInvariant();
+
+        var regMeta = $"{cafeName}||{requestedSlug}";
+        await redis.StringSetAsync($"reg_meta:{phone}", regMeta, TimeSpan.FromSeconds(OtpTtlSeconds));
 
         try
         {
@@ -342,10 +349,25 @@ public class AuthService : IAuthService
         if (storedOtp.IsNullOrEmpty || storedOtp.ToString() != code)
             return (false, null, "INVALID_OTP", "Invalid or expired verification code.");
 
-        var cafeName = (await redis.StringGetAsync($"reg_meta:{phone}")).ToString();
-        if (string.IsNullOrWhiteSpace(cafeName))
+        var regMetaRaw = (await redis.StringGetAsync($"reg_meta:{phone}")).ToString();
+        if (string.IsNullOrWhiteSpace(regMetaRaw))
             return (false, null, "REGISTRATION_EXPIRED", "Registration session expired. Please start again.");
 
+        // Parse "cafeName||slug" format (double-pipe delimiter)
+        string cafeName;
+        string? requestedSlug;
+        var sepIdx = regMetaRaw.IndexOf("||", StringComparison.Ordinal);
+        if (sepIdx >= 0)
+        {
+            cafeName = regMetaRaw[..sepIdx];
+            requestedSlug = regMetaRaw[(sepIdx + 2)..];
+        }
+        else
+        {
+            cafeName = regMetaRaw;
+            requestedSlug = null;
+        }
+
         // Double-check no owner was created in the meantime (race condition guard)
         var alreadyOwner = await _db.Employees
             .AnyAsync(e => e.Phone == phone && e.Role == EmployeeRole.Owner && e.DeletedAt == null, cancellationToken);
@@ -356,8 +378,8 @@ public class AuthService : IAuthService
             return (false, null, "ALREADY_REGISTERED", "An account already exists for this phone number. Please sign in.");
         }
 
-        // Generate a unique slug
-        var slug = await GenerateUniqueSlugAsync(cancellationToken);
+        // Generate a unique slug (try requested slug first, fall back to random)
+        var slug = await GenerateUniqueSlugAsync(requestedSlug, cancellationToken);
 
         var cafe = new Cafe
         {
@@ -402,12 +424,27 @@ public class AuthService : IAuthService
         return (true, tokens, null, null);
     }
 
-    private async Task<string> GenerateUniqueSlugAsync(CancellationToken ct)
+    private async Task<string> GenerateUniqueSlugAsync(string? preferred, CancellationToken ct)
     {
+        // Try the preferred/derived slug first
+        if (Meezi.Core.Utilities.SlugHelper.IsValidSlug(preferred))
+        {
+            if (!await _db.Cafes.AnyAsync(c => c.Slug == preferred, ct))
+                return preferred!;
+
+            // Preferred slug is taken — append a short random suffix
+            for (var i = 0; i < 10; i++)
+            {
+                var candidate = $"{preferred}-{Guid.NewGuid().ToString("N")[..4]}";
+                if (!await _db.Cafes.AnyAsync(c => c.Slug == candidate, ct))
+                    return candidate;
+            }
+        }
+
+        // Full random fallback
         string slug;
         do
         {
-            // e.g. "cafe-a3f9b2c"
             slug = "cafe-" + Guid.NewGuid().ToString("N")[..7];
         } while (await _db.Cafes.AnyAsync(c => c.Slug == slug, ct));
         return slug;