feat: add deep think feature (#311)

* feat: implement backend logic

* feat: implement api/config endpoint

* rename the symbol

* feat: re-implement configuration at client-side

* feat: add client-side of deep thinking

* fix backend bug

* feat: add reasoning block

* docs: update readme

* fix: translate into English

* fix: change icon to lightbulb

* feat: ignore more bad cases

* feat: adjust thinking layout, and implement auto scrolling

* docs: add comments

---------

Co-authored-by: Henry Li <henry1943@163.com>

web/src/core/api/chat.ts

@@ -22,6 +22,7 @@ export async function* chatStream(
     max_step_num: number;
     max_search_results?: number;
     interrupt_feedback?: string;
+    enable_deep_thinking?: boolean;
     enable_background_investigation: boolean;
     report_style?: "academic" | "popular_science" | "news" | "social_media";
     mcp_settings?: {