GUI: add CLI equivalent dialog (#163); use spinboxes in Sequence dialog

and restrict sequence to max 10,000, add button icons;
   make Export dialog sizable and show every 100 results, add button icon;
   fix saving CHANNEL option, fix Export painting main window (Windows), fix
   guard descent not-resetting
 qzint: add getAsCLI(), warnLevel(), extra isStackable()/isComposite() etc
 Add ZBarcode_BarcodeName()
 manual: doc above, some fixes, tweaks

frontend_qt/res/check.svg

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+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-check"><polyline points="20 6 9 17 4 12"></polyline></svg>

frontend_qt/res/delete.svg

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+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-delete"><path d="M21 4H8l-7 8 7 8h13a2 2 0 0 0 2-2V6a2 2 0 0 0-2-2z"></path><line x1="18" y1="9" x2="12" y2="15"></line><line x1="12" y1="9" x2="18" y2="15"></line></svg>