[Bug] AI Assistant crashes with TypeError: Cannot read properties of undefined (reading 'startsWith') in Studio 2025.10.01-sha-8460121

### Describe the bug In Studio version `2025.10.01-sha-8460121`, the AI Assistant fails to load and displays a frontend error. The browser console shows: ``` TypeError: Cannot read properties of undefined (reading 'startsWith') at R (_app-d238bab03b8b0824.js:1:54439) at ProfileImage (726-91818bea6a064d98.js:1:160299) ... ``` The UI message is: > Something went wrong with the AI Assistant > We've been notified and will review and fix this issue. - This error does **not** occur on Studio version `2025.06.30-sha-6f5982d` (AI Assistant works as expected). - The backend API key and connectivity are correct; `/v1/models` returns HTTP 200 from inside the container. - This appears to be a regression in the AI Assistant frontend code, possibly due to a missing or malformed value passed to `ProfileImage` or a related component. ### To Reproduce Steps to reproduce the behavior: 1. Deploy Studio version `2025.10.01-sha-8460121` 2. Open the AI Assistant 3. Observe the crash and error message in the browser console ### Expected behavior The AI Assistant should load and operate as in previous releases without frontend crashes. ### Screenshots N/A ### System Info (please complete the following information): - OS: Ubuntu (Docker) - Browser: Latest Chrome - Studio version: 2025.10.01-sha-8460121 (broken), 2025.06.30-sha-6f5982d (works) ### Additional context - The OpenAI API key and backend health are confirmed working (HTTP 200 for /v1/models) - Pinning Studio to the earlier version resolves the issue ### Labels - frontend - ai - bug