Decor Sounds 0.7.16 beta - Complete indoor/outdoor saved-build exports

Fixes selected-build sharing for builds containing both indoor and outdoor
settings. Builds > select your build > Share selected build opens the interior
export first. Copy it, then use Show Outdoor for the separate outdoor export.
Each section displays its name, section number and room/effect/zone counts.
Both exports use the existing schema-4 format supported by Studio.

All interior assignments come directly from the selected saved snapshot. No
room visits or room-to-house mapping are required. Outdoor zones are grouped
by their exact plot key. Each section includes its own background. Multiple
outdoor plots can be cycled through. Builds with ambiguous multiple interior
house IDs produce an error rather than guessing the destination.

Use Update selected before sharing if you want to include current edits.
Share current house retains the old visited-room filtering. For the complete
saved setup use Share selected build. Publish interior and outdoor separately.

Tested against the supplied saved-variable data: all 42 zones accounted for
exactly once (40 interior, 2 outdoor), plus 12 room assignments, 3 room effects
and both backgrounds. Checked section-button switching, JSON serialization,
copy isolation and compilation of all shipped Lua modules. Live WoW/Studio
publishing remains to be verified. Uploaded user data is not bundled.

Includes New empty build; no Musician/Total RP3 integration. No Studio update.
Install by merging DecorSounds into Interface/AddOns with WoW closed. Preserve
DecorSoundsLibrary, Sounds/User and WTF saved settings.
