fix(editor): version string, NPC ID reset, author attribution + UX

Bug fixes:
- Fix README.txt version from v0.8.0 to v1.0.0
- Reset NPC idCounter_ on loadFromFile to prevent ID collisions
- WCP content pack uses project author/description if loaded instead
  of hardcoded "Kelsi Davis"

New features:
- Select by Type: context menu items for "Select All M2 Models" and
  "Select All WMO Buildings" for batch type-based selection
- selectByType(PlaceableType) added to ObjectPlacer
- Export summary toast now shows object/NPC/quest counts alongside
  file count and open format score (5s duration)

tools/editor/npc_spawner.cpp

@@ -129,6 +129,7 @@ bool NpcSpawner::loadFromFile(const std::string& path) {
 
         spawns_.clear();
         selectedIdx_ = -1;
+        idCounter_ = 1;
 
         for (const auto& js : arr) {
             CreatureSpawn s;