Housing Decor Guide

* Data: Faarden the Builder (Founder's Point) was missing 9 items in
  HDG_VendorDB. Faarden and "Len" Splinthoof at Razorwind Shores are
  paired vendors selling the same 35-item Stormwind line; the original
  scrape stopped at 26. Added: Sturdy Wooden Chair, Sturdy Wooden Bench,
  Reinforced Wooden Chest, Carved Wooden Bar Table, Large Covered Wooden
  Table, Carved Wooden Crate, Wooden Chamberstick, Large Sturdy Wooden
  Table, Tall Sturdy Wooden Chair. Verified against Wowhead.

* Fix: Required Materials list and recipe tooltip showed every reagent
  as 0/1 when adding from the Recipes tab (and other non-Mogul paths).
  Two reagent producers had drifted to different field names (`amount`
  vs `qty`) and the consumers only read `qty`, so non-Mogul queue items
  silently fell back to 1 of each. HDG_Data.InitializeDatabase now
  emits the canonical `qty` field.

* Fix: Acquire tab 3D previews could remain stuck on "Preview unavailable"
  on cold login if the housing catalog landed after HDG had already been
  opened. The HDG_COLLECTION_READY listener was rebuilding the row list
  but not re-running SelectItem, so the right-side preview model and
  "Also sells" gallery were left bound to the pre-catalog (nil) state.
  Listener now re-selects the current item with a forced gallery rebuild.