feat(ai): add ADR-036 unified OCR architecture and frontend test coverage

- Add ADR-036 unified OCR architecture (typhoon-ocr via Ollama)
- Extend AI execution profiles for OCR sandbox configuration
- Add comprehensive frontend test coverage (components, hooks, services)
- Add backend test coverage for document-numbering services
- Update OCR sidecar with typhoon-ocr integration
- Add AI policy service and execution profile management
- Update AGENTS.md and architecture documentation

frontend/lib/api/client.ts

@@ -1,4 +1,6 @@
 // File: lib/api/client.ts
+// Change Log:
+// - 2026-06-13: Export getAuthToken for unit testing
 import axios, { AxiosInstance, InternalAxiosRequestConfig, AxiosError } from 'axios';
 import { v4 as uuidv4 } from 'uuid';
 
@@ -10,7 +12,7 @@ let cachedToken: string | null = null;
 let tokenPromise: Promise<string | null> | null = null;
 
 // Async function to get token
-async function getAuthToken(): Promise<string | null> {
+export async function getAuthToken(): Promise<string | null> {
   if (cachedToken) return cachedToken;
 
   if (tokenPromise) return tokenPromise;