GHSA-95ff-46g6-6gw9

### Summary

An authenticated user with org-level-creator permissions can exploit prototype pollution in the `/api/v2/meta/connection/test` endpoint, causing all database write operations to fail application-wide until server restart.

While the pollution technically bypasses SUPER_ADMIN authorization checks, no practical privileged actions can be performed because database operations fail immediately after pollution.

### Details

The `deepMerge()` function in `packages/nocodb/src/utils/dataUtils.ts` does not sanitize the following keys: (`__proto__`, `constructor`, `prototype`):

```typescript export const deepMerge = (target: any, ...sources: any[]) => { // ... Object.keys(source).forEach((key) => { if (isMergeableObject(source[key])) { if (!target[key]) target[key] = Array.isArray(source[key]) ? [] : {}; deepMerge(target[key], source[key]); // Recursively merges __proto__ } else { target[key] = source[key]; } }); // ... }; ```

The `testConnection` endpoint (`packages/nocodb/src/controllers/utils.controller.ts`) passes user-controlled input directly to `deepMerge()`:

```typescript config = await integration.getConfig(); deepMerge(config, body); ```

When an attacker sends `{"__proto__": {"super": true}}`, the `super` property is written to `Object.prototype`, affecting all plain objects in the Node.js process.

## Impact

Pollutes Object.prototype globally, breaking all subsequent database write operations for all users until process restart.