Complete build wiring and CLI file commands

Align documented commands with the CLI, enable optional GUI/test targets, and remove committed API secrets so the project is safer to build and run.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dstalk-gui/src/main.cpp

@@ -35,7 +35,6 @@ int main(int argc, char* argv[])
         return 1;
     }
 
-    /* TODO: 主循环 — SDL 事件处理, UI 渲染, 调用 dstalk_chat */
     bool running = true;
     SDL_Event event;
     while (running) {