chore(deps): happy-dom 20.9 → 20.14 breaks DOM-event renderer tests #1365

Dependabot #1322 moved happy-dom 20.9.0 → 20.14.5, and its quality-gate (run 36168289491) failed on DOM-event tests:

• the real-xterm wheel boundary (terminalWheelBoundary.xterm.renderer.test.ts: plain/Alt scrollback, exhausted wheels at top and bottom, alternate-screen and mouse-reporting wheels);
• keybinding-recorder click/focus handling (clicking elsewhere, window blur, scrollbar drag, gap clicks, stopPropagation);
• pane resume ("stays open and says why when no pane is selected", "no unhandled rejection when a new-tab resume fails").

#1360 took #1322's other 20 bumps with happy-dom held at 20.9.0, and its CI is green, which confirms happy-dom as the cause.

The move needs its own investigation: which happy-dom change (20.10–20.14) altered event dispatch, and whether the tests or their shims (the real-xterm test already needs three happy-dom shims) must change. Do not force it through by weakening those tests.