Backend: add apt-get install libsqlcipher-dev before pip install so
pysqlcipher3 builds in the runner image.
Frontend: prep.test.ts was missing a qa mock (fetchFor now calls 5
endpoints in parallel; tests only mocked 4 — 5th returned undefined,
threw in catch, research.value never set). survey.test.ts: analyze()
was refactored from sync-result to async-task+poll; update test to
mock POST then poll completion.
Also remove Classic UI (Streamlit) button from AppNav — Streamlit is
deprecated and the button caused an unrecoverable redirect loop.