feat(auth): admin-issued café recovery key login

Platform admins can generate a permanent recovery key per café (admin
panel → Cafés). The café Owner uses it to sign in when OTP access is lost;
once authenticated, all server-side data syncs as normal (data is per-café
on the server, the device only caches it).

Backend:
- Cafe.RecoveryKeyHash (SHA-256, unique index) + RecoveryKeyCreatedAt; migration
- RecoveryKeyGenerator util: MZ-XXXXX-XXXXX-XXXXX-XXXXX, ~190-bit entropy,
  stored as SHA-256 (API-token pattern — raw key shown once, never retrievable)
- Admin: POST/DELETE /api/admin/cafes/{id}/recovery-key (key returned once);
  café list now reports HasRecoveryKey + RecoveryKeyCreatedAt
- Login: POST /api/auth/login-key → exact-hash lookup → resolves café Owner →
  issues normal JWT; rate-limited (auth-otp), suspended/no-owner guarded, logged

Admin UI: per-café generate / regenerate / revoke with one-time reveal + copy.
Dashboard login: discreet "ورود با کلید بازیابی" link → key field. fa/en/ar.

86 tests pass; all tsc clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Meezi.API/Controllers/AuthController.cs

@@ -58,6 +58,23 @@ public class AuthController : ControllerBase
         return Ok(new ApiResponse<AuthTokenResponse>(true, data));
     }
 
+    [HttpPost("login-key")]
+    [EnableRateLimiting("auth-otp")]
+    [ProducesResponseType(typeof(ApiResponse<AuthTokenResponse>), StatusCodes.Status200OK)]
+    public async Task<IActionResult> LoginWithRecoveryKey(
+        [FromBody] LoginWithRecoveryKeyRequest request,
+        CancellationToken cancellationToken)
+    {
+        if (string.IsNullOrWhiteSpace(request.Key))
+            return BadRequest(ValidationError("Recovery key is required."));
+
+        var (success, data, code, message) = await _authService.LoginWithRecoveryKeyAsync(request, cancellationToken);
+        if (!success)
+            return ErrorResult(code!, message!);
+
+        return Ok(new ApiResponse<AuthTokenResponse>(true, data));
+    }
+
     [HttpPost("send-otp")]
     [EnableRateLimiting("auth-otp")]
     [ProducesResponseType(typeof(ApiResponse<SendOtpResponse>), StatusCodes.Status200OK)]
@@ -224,7 +241,9 @@ public class AuthController : ControllerBase
         "RATE_LIMITED" => StatusCode(StatusCodes.Status429TooManyRequests,
             new ApiResponse<object>(false, null, new ApiError(code, message))),
         "NOT_FOUND" => NotFound(new ApiResponse<object>(false, null, new ApiError(code, message))),
-        "INVALID_OTP" or "INVALID_TOKEN" => Unauthorized(new ApiResponse<object>(false, null, new ApiError(code, message))),
+        "INVALID_OTP" or "INVALID_TOKEN" or "INVALID_KEY" => Unauthorized(new ApiResponse<object>(false, null, new ApiError(code, message))),
+        "CAFE_SUSPENDED" or "NO_OWNER" => StatusCode(StatusCodes.Status403Forbidden,
+            new ApiResponse<object>(false, null, new ApiError(code, message))),
         "BRANCH_FORBIDDEN" => StatusCode(StatusCodes.Status403Forbidden,
             new ApiResponse<object>(false, null, new ApiError(code, message))),
         "ALREADY_REGISTERED" => Conflict(new ApiResponse<object>(false, null, new ApiError(code, message))),