feat(audio): add audio.transcribe tool with Whisper-compatible API support

- Add createAudioTranscribeTool with OpenAI/Groq/Ollama/llama.cpp provider support
- Refactor audio config schema to nested audio.enabled + audio.provider structure
- Move audio tool registration to initTools() for conditional enablement
- Fix duplication bug in audio-transcribe.ts URL download handler
- Support base64 data and URL-based audio input with format detection

src/daemon/tools.ts

@@ -1,7 +1,8 @@
 import type { Config } from '../config/index.js';
 import type { Lifecycle } from './lifecycle.js';
+import type { AudioTranscriptionConfig } from '../models/media.js';
 import { HookEngine } from '../hooks/index.js';
-import { ToolRegistry, ToolExecutor, ToolPolicy, allBuiltinTools, createWebSearchTools, createProcessTools, ProcessManager, BrowserManager, createBrowserTools } from '../tools/index.js';
+import { ToolRegistry, ToolExecutor, ToolPolicy, allBuiltinTools, createWebSearchTools, createProcessTools, ProcessManager, BrowserManager, createBrowserTools, createAudioTranscribeTool } from '../tools/index.js';
 
 export interface ToolsDeps {
   config: Config;
@@ -52,6 +53,18 @@ export function initTools(deps: ToolsDeps): ToolsResult {
     console.log('Process manager stopped');
   });
 
+  // Register audio transcription tool if configured
+  if (config.audio?.enabled && config.audio.provider) {
+    const audioConfig: AudioTranscriptionConfig = {
+      endpoint: config.audio.provider.endpoint,
+      apiKey: config.audio.provider.api_key,
+      model: config.audio.provider.model,
+    };
+    const audioTool = createAudioTranscribeTool(audioConfig);
+    toolRegistry.register(audioTool);
+    console.log(`Audio transcription enabled (type=${config.audio.provider.type}, endpoint=${audioConfig.endpoint})`);
+  }
+
   // Initialize browser manager and register browser tools (if enabled)
   let browserManager: BrowserManager | undefined;
   if (config.browser?.enabled) {