BUG-012: Reposition side panel toggle button (top-[52px]→top-20) to
avoid overlap with header buttons in ResizableChatLayout.
BUG-013: Install @tailwindcss/typography plugin and import in index.css
to enable prose-* Markdown rendering classes in StreamingText.
BUG-007: Rewrite authStore tests to match HttpOnly cookie auth model
(login takes 1 arg, no token/refreshToken in state). Rewrite request
interceptor tests for cookie-based auth. Update bug-tracker status.