addon-image: Kitty graphics q=2 should suppress OK responses too

[sotasan]

Per the Kitty graphics protocol spec:

If you wish, you can suppress all responses by setting q=2. To suppress responses only for the OK status, set q=1.

The current _sendResponse implementation in KittyGraphicsHandler.ts only matches quiet === 1 for OK and quiet === 2 for errors, so a transmission with q=2 still emits an OK response — a violation of the spec and a real-world breakage for crossterm-based clients (e.g. yazi) that send q=2 precisely to get silence and whose input parser misinterprets the unsolicited APC response as keystrokes. Concretely, hovering over an image in yazi pumps ESC _ G i = N ; O K ESC \ into stdin, which crossterm reads as ; (open shell command line), G (jump to bottom), O (open with).

Changes quiet === 1 → quiet >= 1 for OK and quiet === 2 → quiet >= 2 for errors, making q=2 suppress both. Adds 4 tests mirroring the existing q=1 OK-suppression coverage:

• Query (a=q): "suppresses OK response when q=2"
• Transmit-only (a=t): "a=t OK suppressed by q=2"
• Transmit-display (a=T): "a=T OK suppressed by q=2"
• Placement (a=p): "OK response suppressed by q=2"

The 2-character behavior change has been validated end-to-end in a downstream xterm.js consumer where yazi previews now work cleanly.