chore: add WebSocket API with Mongoose, service management, and AI command execution

Add new WebSocket API module (api.c/api.h) using Mongoose library for real-time
window manager control, including workspace and client status endpoints.
Introduce service management module (services.h) with init/run/cleanup lifecycle.
Extend AI module to parse [WM_CMD:] directives from responses and forward JSON
commands to the API handler. Update config with api.enabled, api.port, and
services.path settings. Integrate new modules into main init/run/cleanup flow.

include/api.h

@@ -0,0 +1,16 @@
+/*
+ * DWN - Desktop Window Manager
+ * WebSocket API
+ */
+
+#ifndef DWN_API_H
+#define DWN_API_H
+
+#include <stdbool.h>
+
+void api_init(void);
+void api_process(void);
+void api_cleanup(void);
+void api_handle_json_command(const char *json_str);
+
+#endif

include/config.h

@@ -60,6 +60,10 @@ struct Config {
     bool autostart_xdg;
     char autostart_path[512];
 
+    char services_path[512];
+    bool api_enabled;
+    int api_port;
+
     int demo_step_delay_ms;
     int demo_ai_timeout_ms;
     int demo_window_timeout_ms;

include/services.h

@@ -0,0 +1,13 @@
+/*
+ * DWN - Desktop Window Manager
+ * Service management
+ */
+
+#ifndef DWN_SERVICES_H
+#define DWN_SERVICES_H
+
+void services_init(void);
+void services_run(void);
+void services_cleanup(void);
+
+#endif