AJAX fragment: extract #main-panel with matching close tag (depth
tracking) instead of taking everything to end of file. Prevents
shell closing tags from breaking the DOM swap.
Back button test: verifies content actually changes — checks for
"Geography" and "Rendering Pipeline" after going back, not just
that body has >100 chars. Tests forward nav content change too.
7/7 navigation tests pass including back button content verification.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
58d6a6de07