feat: 支持多语言提示词本地化和界面优化

- 添加 prompt_locale 参数支持简体中文、繁体中文和英文提示词本地化
- 移除内置 agents 配置以简化系统架构
- 更新 ContextBuilder 使用动态提示词模板而非硬编码内容
- 在 AgentLoop、Web 接口和 AgentService 中传递 locale 参数
- 添加输出语言指令确保用户界面内容按指定语言生成
- 扩展前端 LanguageSwitcher 组件支持三种语言选项
- 优化 Header 和侧边栏组件的响应式布局和文本截断处理
- 更新测试用例验证不同语言环境下的提示词正确性

app-instance/backend/beaver/engine/context/builder.py

@@ -27,13 +27,7 @@ from dataclasses import dataclass, field
 from typing import Any
 
 from beaver.memory.curated.snapshot import MemorySnapshot
-
-
-BEAVER_USER_ASSISTANT_IDENTITY_PROMPT = (
-    "You are 海狸 (Beaver), an AI assistant developed by 博维资讯系统有限公司. "
-    "When communicating with users, keep this identity consistent. "
-    "If users ask who you are, say that you are 海狸 (Beaver), 博维资讯系统有限公司研发的 AI 助手."
-)
+from beaver.prompts import get_main_agent_prompt
 
 
 @dataclass(slots=True)
@@ -113,6 +107,7 @@ class ContextBuildInput:
     """
 
     base_system_prompt: str = ""
+    prompt_locale: str | None = None
     history: list[dict[str, Any]] = field(default_factory=list)
     current_user_input: str | list[dict[str, Any]] | None = None
     memory_snapshot: MemorySnapshot | None = None
@@ -171,7 +166,7 @@ class ContextBuilder:
         - activated skill 正文放到显式消息里，避免 system prompt 持续膨胀
         """
 
-        sections: list[str] = [BEAVER_USER_ASSISTANT_IDENTITY_PROMPT]
+        sections: list[str] = [get_main_agent_prompt(build_input.prompt_locale)]
 
         base_system_prompt = (build_input.base_system_prompt or "").strip()
         if base_system_prompt:

app-instance/backend/beaver/engine/loop.py

@@ -224,6 +224,7 @@ class AgentLoop:
         title: str | None = None,
         execution_context: str | None = None,
         skill_selection_context: str | None = None,
+        prompt_locale: str | None = None,
         model: str | None = None,
         provider_name: str | None = None,
         api_key: str | None = None,
@@ -275,6 +276,7 @@ class AgentLoop:
             title=title,
             execution_context=execution_context,
             skill_selection_context=skill_selection_context,
+            prompt_locale=prompt_locale,
             model=model,
             provider_name=provider_name,
             api_key=api_key,
@@ -314,6 +316,7 @@ class AgentLoop:
         title: str | None = None,
         execution_context: str | None = None,
         skill_selection_context: str | None = None,
+        prompt_locale: str | None = None,
         model: str | None = None,
         provider_name: str | None = None,
         api_key: str | None = None,
@@ -572,6 +575,7 @@ class AgentLoop:
 
             build_input = ContextBuildInput(
                 base_system_prompt=self.profile.system_prompt,
+                prompt_locale=prompt_locale,
                 history=session_manager.get_history(
                     resolved_session_id,
                     max_messages=max(1, self.profile.max_context_messages),