The reverted code had two bugs in the tab switching logic:
1. closeNavigate() called switchTab() -> infinite recursion since
switchTab() calls closeNavigate() when leaving tabNavigate
2. currentTab was updated AFTER closeNavigate(), so the recursive
call hit the same condition over and over
Fix: move currentTab assignment before cleanup, use a wasNavigating
flag to track the old tab state, and make closeNavigate() only reset
nav UI (caller handles tab transition).
Previously relied on module-level env var which got overwritten
when frontend tests' conftest.py test_db_path fixture ran first.
Now explicitly sets env var inside client fixture + invalidates
caches before import. Also fixed importlib order.
The F2 auto-populate address block was accidentally inserted inside
the payload={} object literal, causing a JS syntax error that
broke the entire script and prevented the login screen from showing.
shawn