feat(streaming): add streaming support to DriverAgent and DualAgentOrchestrator

- Add onToken callback option to IDualAgentOptions interface
- Add onToken property and setOnToken method to DriverAgent
- Wire up streaming in startTask and continueWithMessage methods
- Pass source identifier ('driver'/'guardian') to onToken callback

ts/smartagent.interfaces.ts

@@ -34,6 +34,8 @@ export interface IDualAgentOptions extends plugins.smartai.ISmartAiOptions {
   onProgress?: (event: IProgressEvent) => void;
   /** Prefix for log messages (e.g., "[README]", "[Commit]"). Default: empty */
   logPrefix?: string;
+  /** Callback fired for each token during LLM generation (streaming mode) */
+  onToken?: (token: string, source: 'driver' | 'guardian') => void;
 }
 
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