Rename 'Grading' to 'Demo' in sign-in UI and error messages

Update changelog with Invest Insight, edit backend, and UX fixes

Fix chart colors and follow-up suggestions

Fix browser password autofill on chat input field

Add edit button for backend connections

Add Invest Insight as third backend provider

Fix ruff format violations in 6 files

Add OpenRouter support, fix Rotki tests, polish docs for open source

Add seed data files for portfolio import testing

Pass _source field through all tools to prevent backend hallucination

Fix CombinedProvider crash: handle dict-style holdings from Ghostfolio

Add debug/portfolio endpoint to diagnose tool failures

Add commit hash to health endpoint for deploy verification

Add diagnostic logging for Rotki provider debugging

Handle Rotki 409 conflict and add crypto keywords to guardrails