feat: add DELETE /api/cases/:caseId to fully delete a case

Chat panel's trash icon should remove the whole case (not just clear
its chat history) — documents/analyses/chat_messages cascade-delete
via the existing ON DELETE CASCADE foreign keys.

src/routes/index.ts

@@ -2,6 +2,7 @@ import { Router } from 'express';
 import documentRoutes from './document.routes';
 import chatRoutes from './chat.routes';
 import precedentRoutes from './precedent.routes';
+import caseRoutes from './case.routes';
 
 const router = Router();
 
@@ -11,6 +12,7 @@ router.get('/health', (req, res) => {
 
 router.use('/documents', documentRoutes);
 router.use('/chat', chatRoutes);
+router.use('/cases', caseRoutes);
 router.use('/', precedentRoutes); // Keeps the same paths like /api/search-precedents
 
 export default router;