3.11.17

release: v3.11.17 — broken/clear actually clears

The SPA's 'Clear All' button POSTs /__dev/api/broken/clear, which was
calling error_tracker.clear_resolved. That only removed errors the user
had individually marked resolved — the panel kept showing every other
captured error after Clear All was pressed. Switch to clear_all so the
button does what it says. Matches PHP/Python/Node parity.