Decor Sounds 0.7.14 beta — New empty build

- Added New empty build to the Builds tab. Enter a new name in Build name,
  click New empty build and confirm.
- Clears active room backgrounds/effects, house and outdoor backgrounds, zones,
  room names and house/room game-audio policies. Quiet house is switched off and
  any game-audio settings muted by Decor Sounds are restored.
- Saves the previous setup as a named recovery build before resetting, including
  unfinished room/background/zone form drafts. Existing builds are preserved.
- Undo load / reset / relink can immediately restore the preceding setup.
  The named recovery build remains available after subsequent edits or reloads.
- Shared sound library, favourites, personal volume settings and WoW house/decor
  remain untouched. No Studio update or audio reprocessing is required.
- Build loading restores saved room ownership mappings when available and clears
  unrelated form drafts. Recovery builds restore their saved form drafts.
- Empty/duplicate names are rejected before modifying any settings.
- Based on 0.7.12. Discarded 0.7.13 Musician/Total RP3 integration is not included.

Multiple houses: save each sound setup as a build and load it manually when
switching houses. This release does not automatically select builds by house.
A new empty build clears ALL active sound assignments, not only the current room
or property. Your previous assignments remain in the recovery build.

Validation: Lua 5.1 full-addon mock tests passed for confirmation, invalid names,
empty reset, recovery, undo, unfinished drafts, library/build preservation and
older snapshots. The new button still needs an in-game visual check.
