Muq + WOWSlider Iframe Deck (Incremental Patch)

Muq
- Clone of Luq UI + resumable upload/download panels.
- Adds Muq.Web.Controllers.FileController:
  - GET  /Muq/api/file/ping
  - GET  /Muq/api/file/pull?root=...&relHex=...&asText=1
  - POST /Muq/api/file/push   (root, relHex, dataHex, mode=write|append, renameFromHex optional)
  - POST /Muq/api/file/pushpull (root, relHex, dataHex, pullRelHex optional)
- Hex is UTF-8 bytes encoded as hex (even length). Supports 0x prefix.

Config
- Add appSetting Muq.AllowedRoots (or Luq.AllowedRoots fallback):
  key=value;key=value;...

WOWSlider Iframe Deck
- ___Fire/wwwroot/doublewow_iframe_deck.js
- Anchors under Parentop.Wsliders[nn] (nn from engineNN folder or container id).
- Provides:
  Parentop.Wsliders[nn].AttachIframe(panelKey, iframeEl)
  Parentop.Wsliders[nn].SetActive(panelKey)
  Parentop.Wsliders[nn].Move(fromIdx,toIdx)
  Parentop.Wsliders[nn].MoveKey(panelKey,toIdx)
  Parentop.Wsliders[nn].Reindex()