feat: add POST /api/precedent-analysis for research "Analiz modu"

Takes the user's described situation plus the top search results and
asks the AI model for a short legal assessment. Auth-protected since
it's a paid AI call.

src/routes/precedent.routes.ts

@@ -1,9 +1,11 @@
 import { Router } from 'express';
-import { searchPrecedents, getPrecedentDocument } from '../controllers/precedent.controller';
+import { requireAuth } from '../middleware/auth';
+import { searchPrecedents, getPrecedentDocument, analyzePrecedents } from '../controllers/precedent.controller';
 
 const router = Router();
 
 router.post('/search-precedents', searchPrecedents);
 router.get('/precedent-document/:documentId', getPrecedentDocument);
+router.post('/precedent-analysis', requireAuth, analyzePrecedents);
 
 export default router;