Adds a reload button to the app titlebar visible only in PWA standalone
or fullscreen mode, and a pull-to-refresh gesture on the messages container
that smooth-scrolls to the top before activating.
The reload button sits next to the message count label and provides a
one-tap refresh for users who installed the WebUI as a home-screen app
where browser navigation controls are unavailable.
The pull-to-refresh gesture detects downward drag at the top of the
message list, shows a visual indicator ('Pull to refresh' / 'Release to refresh'),
and reloads on release past the 80px threshold. When triggered mid-conversation,
it smooth-scrolls to the top first.
Opus advisor review of stage-375 flagged that the protected-bracket set including `<` and `>` caused tables containing comparison operators across adjacent columns to mis-collapse: `| x < 5 | y > 10 |` matched `< ... >` as a bracket pair and stashed the inner pipe, producing one cell instead of two.
Real LLM table output uses angle brackets as comparison operators far more often than as content-grouping pairs, so the safer default is to NOT treat them as a matched pair. Dropped `<` from the opener class and `>` from both closer classes.
Three regression tests added (`TestComparisonOperatorsAcrossColumns` class): `< … >` across columns, `<` alone, `>` alone.
PR #2428's iterative _protectPipes regex introduced two issues we caught during stage assembly:
1. The negated character classes [^)\]}'>] added `'` as a stop character. That breaks cells containing string-literal pipes like `('a'|'b')` (Python type-union examples) — they would still mis-split. Dropped the apostrophe-stop.
2. The literal `}` inside the regex character classes confused the brace-counting extractFunc driver in tests/test_renderer_js_behaviour.py, breaking all 45 existing node-driven renderer tests. Rewrote both brace literals as hex escapes (\\x7b and \\x7d) — semantically identical at the regex-engine level but the JS source carries no bare brace glyph.
Also added tests/test_issue2428_table_pipe_protection.py with 9 regression tests covering single-pipe, multi-pipe-in-brackets, apostrophes-with-pipes, and the KaTeX \$...\$ guard.
