Add Redis-based permission caching for users and subusers

- Introduced Redis-backed caching for user and subuser permission evaluations in the `route_t` trait, reducing database queries.
- Enhanced `Redis` class with methods for permission caching: `cache_permission`, `get_permission`, and `clear_permission`.
- Added test coverage for the new caching logic in `PermissionRedisCacheTest.php`.
- Implemented Redis caching for authentication sessions with `cache_auth_session`, `get_auth_session`, and `clear_auth_session`.
- Improved CORS handling for preflight requests in `index.php`.

services/nginx/app/interfaces/redis_i.php

@@ -266,4 +266,50 @@ interface redis_i
      * @return self
      */
     public function clear_customer_number_from_user_id(int $user_id): self;
+
+    /**
+     * Cache an auth session payload for a given token
+     * @param string $token
+     * @param array $session
+     * @param int $ttl Seconds to keep in cache
+     * @return self
+     */
+    public function cache_auth_session(string $token, array $session, int $ttl = 60): self;
+
+    /**
+     * Get a cached auth session payload by token
+     * @param string $token
+     * @return array|null
+     */
+    public function get_auth_session(string $token): array|null;
+
+    /**
+     * Clear a cached auth session payload by token
+     * @param string $token
+     * @return self
+     */
+    public function clear_auth_session(string $token): self;
+
+    /**
+     * Cache a permission evaluation
+     * @param string $cache_key
+     * @param bool $allowed
+     * @param int $ttl
+     * @return self
+     */
+    public function cache_permission(string $cache_key, bool $allowed, int $ttl = 300): self;
+
+    /**
+     * Get a cached permission evaluation
+     * @param string $cache_key
+     * @return bool|null
+     */
+    public function get_permission(string $cache_key): bool|null;
+
+    /**
+     * Clear a cached permission evaluation
+     * @param string $cache_key
+     * @return self
+     */
+    public function clear_permission(string $cache_key): self;
 }