feat: add model tracking and reporting across pipeline

- Track actual model name from router through audit logs, session.json, and query output
- Add router-utils.ts to resolve model names from ROUTER_DEFAULT env var
- Inject model info into final report's Executive Summary section
- Update documentation with supported providers, pricing, and config examples
- Update router-config.json with latest model versions (GPT-5.2, Gemini 2.5, etc.)

src/phases/pre-recon.ts

@@ -18,9 +18,9 @@ import type { DistributedConfig } from '../types/config.js';
 interface AgentResult {
   success: boolean;
   duration: number;
-  cost?: number;
-  error?: string;
-  retryable?: boolean;
+  cost?: number | undefined;
+  error?: string | undefined;
+  retryable?: boolean | undefined;
 }
 
 type ToolName = 'nmap' | 'subfinder' | 'whatweb' | 'schemathesis';