feat(voice): 新增本地语音识别(ASR)提供商选项

新增 `voice.asr_provider` 配置项，允许用户在 "api" 和 "local" 之间选择语音识别服务。

当设置为 "local" 时，系统将通过 `local_asr` 工具（由 `stt_whisper_plugin` 插件提供）调用本地 Whisper 模型进行语音转文字。这为用户提供了一个不依赖外部 API、注重隐私的备选方案。

- 默认值仍为 "api"，保持现有行为不变。
- 添加 `openai-whisper` 作为新的依赖项以支持此功能。

src/plugins/built_in/stt_whisper_plugin/__init__.py

@@ -0,0 +1,9 @@
+from src.plugin_system.base.plugin_metadata import PluginMetadata
+
+__plugin_meta__ = PluginMetadata(
+    name="Whisper本地语音识别",
+    description="通过OpenAI Whisper模型提供本地语音转文字的功能",
+    usage="在 bot_config.toml 中将 asr_provider 设置为 'local' 即可启用",
+    version="0.1.0",
+    author="Elysia",
+)

src/plugins/built_in/stt_whisper_plugin/plugin.py

@@ -0,0 +1,115 @@
+import asyncio
+import os
+import tempfile
+from typing import Any
+from pathlib import Path
+import toml
+
+import whisper
+
+from src.common.logger import get_logger
+from src.plugin_system import BasePlugin, ComponentInfo, register_plugin
+from src.plugin_system.base.base_tool import BaseTool
+from src.plugin_system.base.component_types import ComponentType, ToolInfo
+
+logger = get_logger("stt_whisper_plugin")
+
+# 全局变量来缓存模型，避免重复加载
+_whisper_model = None
+_is_loading = False
+
+class LocalASRTool(BaseTool):
+    """
+    本地语音识别工具
+    """
+    tool_name = "local_asr"
+    tool_description = "将本地音频文件路径转换为文字。"
+    tool_parameters = [
+        {"name": "audio_path", "type": "string", "description": "需要识别的音频文件路径", "required": True}
+    ]
+
+    @classmethod
+    async def load_model_once(cls, plugin_config: dict):
+        """
+        一个类方法，用于在插件加载时触发一次模型加载。
+        """
+        global _whisper_model, _is_loading
+        if _whisper_model is None and not _is_loading:
+            _is_loading = True
+            try:
+                model_size = plugin_config.get("whisper", {}).get("model_size", "tiny")
+                device = plugin_config.get("whisper", {}).get("device", "cpu")
+                logger.info(f"正在预加载 Whisper ASR 模型: {model_size} ({device})")
+                
+                loop = asyncio.get_running_loop()
+                _whisper_model = await loop.run_in_executor(
+                    None, whisper.load_model, model_size, device
+                )
+                logger.info(f"Whisper ASR 模型 '{model_size}' 预加载成功!")
+            except Exception as e:
+                logger.error(f"预加载 Whisper ASR 模型失败: {e}")
+                _whisper_model = None
+            finally:
+                _is_loading = False
+
+    async def execute(self, function_args: dict) -> str:
+        audio_path = function_args.get("audio_path")
+        if not audio_path:
+            return "错误：缺少 audio_path 参数。"
+
+        global _whisper_model
+        # 增强的等待逻辑：只要模型还没准备好，就一直等待后台加载任务完成
+        while _is_loading:
+            await asyncio.sleep(0.2)
+        
+        if _whisper_model is None:
+            return "Whisper 模型加载失败，无法识别语音。"
+        
+        try:
+            logger.info(f"开始使用 Whisper 识别音频: {audio_path}")
+            loop = asyncio.get_running_loop()
+            result = await loop.run_in_executor(
+                None, _whisper_model.transcribe, audio_path
+            )
+            text_result = result.get("text", "")
+            text = str(text_result).strip()
+            logger.info(f"音频识别成功: {text}")
+            return text
+        except Exception as e:
+            logger.error(f"使用 Whisper 识别音频失败: {e}")
+            return f"语音识别出错: {e}"
+
+@register_plugin
+class STTWhisperPlugin(BasePlugin):
+    plugin_name = "stt_whisper_plugin"
+    config_file_name = "config.toml"
+    python_dependencies = ["openai-whisper"]
+
+    async def on_plugin_loaded(self):
+        """
+        插件加载完成后的钩子，用于触发模型预加载。
+        """
+        try:
+            from src.config.config import global_config
+            if global_config.voice.asr_provider == "local":
+                # 使用 create_task 在后台开始加载，不阻塞主流程
+                asyncio.create_task(LocalASRTool.load_model_once(self.config or {}))
+        except Exception as e:
+            logger.error(f"触发 Whisper 模型预加载时出错: {e}")
+
+    def get_plugin_components(self) -> list[tuple[ComponentInfo, type]]:
+        """根据主配置动态注册组件"""
+        try:
+            from src.config.config import global_config
+            if global_config.voice.asr_provider == "local":
+                logger.info("ASR provider is 'local', enabling local_asr tool.")
+                return [(ToolInfo(
+                    name=LocalASRTool.tool_name,
+                    description=LocalASRTool.tool_description,
+                    component_type=ComponentType.TOOL
+                ), LocalASRTool)]
+        except Exception as e:
+            logger.error(f"检查 ASR provider 配置时出错: {e}")
+        
+        logger.debug("ASR provider is not 'local', whisper plugin's tool is disabled.")
+        return []