Add Warcraft III item effects, Tiny Structures, and construction occupant handling

[sookyboo]

• Implement Bundle of Lumber, Mana Rune, and gold or lumber kill bounty rewards, including resource feedback and effects.
• Add Tiny Structure item construction with placement preview, race-aware Tiny Great Hall resolution, authored build times, and item consumption on successful placement.
• Improve construction placement and completion: relocate units from building footprints, preserve hidden workers, and reserve distinct exits for occupants.
• Add JASS unit and widget item-drop support.
• Add regression coverage and update Warcraft III gameplay and ability documentation.
• Fix SLK fixture const usage and legacy campaign backdrop key formatting.