Add atomic reservation support in Redis for goal alert deduplication with expiration. Update Cron logic and add unit tests for validation.

services/nginx/app/classes/redis.php

@@ -450,6 +450,21 @@ class redis implements redis_i
         return 'temporary_cache_' . uniqid();
     }
 
+    /**
+     * Atomically set a key with TTL only when it does not already exist.
+     */
+    public function set_if_absent_with_expiration(string $key, string $value, int $seconds): bool
+    {
+        if (!self::is_connected()) {
+            self::connect();
+        }
+
+        $seconds = max(1, $seconds);
+        $result = $this->redis->set($key, $value, 'EX', $seconds, 'NX');
+
+        return $result === true || strtoupper((string)$result) === 'OK';
+    }
+
     public function mget(array $array_map): array
     {
         // Get multiple keys from Redis
@@ -485,4 +500,4 @@ class redis implements redis_i
         $this->delete('perm:' . $cache_key);
         return $this;
     }
-}
+}