[Feature] E2E: MemoryDebugPanel settings interaction #209

Summary

Add E2E coverage for the MemoryDebugPanel in settings — namespace browsing, document viewing, deletion.

Problem

MemoryDebugPanel (app/src/components/settings/panels/MemoryDebugPanel.tsx) is fully implemented but has no E2E test coverage.

Acceptance criteria

• Navigate — Open Settings → Memory Debug panel
• Browse — List namespaces, select one, view documents
• View — Open a document, verify content displayed
• Delete — Delete a document, verify removal from list
• Query/Recall — Run a query and recall from the debug panel

Related

Parent: #190
File: app/src/components/settings/panels/MemoryDebugPanel.tsx