feat(editor): add standalone world editor (rough/WIP)

Standalone wowee_editor tool for creating custom WoW zones.
This is a rough initial implementation — many features work but
M2/WMO rendering still has issues (frame sync, texture layout
transitions) and needs further polish.

Terrain:
- Create new blank terrain with 10 biome types (Grassland, Forest,
  Jungle, Desert, Barrens, Snow, Swamp, Rocky, Beach, Volcanic)
- Load existing ADT tiles from extracted game data
- Sculpt brushes: Raise, Lower, Smooth, Flatten, Level
- Chunk edge stitching prevents seams between tiles
- Undo/redo (100-deep stack, Ctrl+Z/Ctrl+Shift+Z)
- Save to WoW ADT/WDT format

Texture Painting:
- Paint/Erase/Replace Base modes
- Full tileset texture browser (1285 textures from manifest)
- Per-zone directory filtering and search
- Alpha map editing with 4-layer limit (auto-replaces weakest)

Object Placement:
- M2 and WMO model placement with full manifest browser (11k M2s, 2k WMOs)
- M2Renderer + WMORenderer integrated (loads .skin files for WotLK)
- Ghost preview follows cursor before placing
- Ctrl+click selection, right-click context menu
- Transform gizmo (Move/Rotate/Scale with axis constraints)
- Position/rotation/scale editing in properties panel

NPC/Monster System:
- 631 creature presets scanned from manifest, categorized
  (Critters, Beasts, Humanoids, Undead, Demons, etc.)
- Stats editor: level, health, mana, damage, armor, faction
- Behavior: Stationary, Patrol, Wander, Scripted
- Aggro/leash radius, respawn time, flags (hostile/vendor/etc.)
- Save creature spawns to JSON

Water:
- Place water at configurable height per chunk
- Liquid types: Water, Ocean, Magma, Slime
- Rendered as translucent colored quads
- Saved in ADT MH2O format

Infrastructure:
- Free-fly camera (WASD/QE, right-drag look, scroll speed)
- 5-mode toolbar: Sculpt | Paint | Objects | Water | NPCs
- Asset browser indexes full manifest on startup
- Editor water/marker shaders (pos+color vertex format)
- forceNoCull added to M2Renderer for editor use
- AssetManifest::getEntries() and AssetManager::getManifest() exposed

Known issues:
- M2/WMO rendering may not display on first placement (frame index
  sync between update/render was misaligned — now fixed but untested
  end-to-end)
- Validation layer errors on shutdown (resource cleanup ordering)
- Object placement on steep terrain can miss raycast
- No undo for texture painting or object placement yet

tools/editor/npc_spawner.cpp

@@ -0,0 +1,111 @@
+#include "npc_spawner.hpp"
+#include "core/logger.hpp"
+#include <fstream>
+#include <sstream>
+#include <cmath>
+#include <algorithm>
+#include <filesystem>
+
+namespace wowee {
+namespace editor {
+
+uint32_t NpcSpawner::nextId() { return idCounter_++; }
+
+void NpcSpawner::placeCreature(const CreatureSpawn& spawn) {
+    CreatureSpawn s = spawn;
+    s.id = nextId();
+    s.selected = false;
+    spawns_.push_back(s);
+    LOG_INFO("Creature placed: ", s.name, " (id=", s.id, ") at (",
+             s.position.x, ",", s.position.y, ",", s.position.z, ")");
+}
+
+void NpcSpawner::removeCreature(int index) {
+    if (index < 0 || index >= static_cast<int>(spawns_.size())) return;
+    spawns_.erase(spawns_.begin() + index);
+    if (selectedIdx_ == index) selectedIdx_ = -1;
+    else if (selectedIdx_ > index) selectedIdx_--;
+}
+
+int NpcSpawner::selectAt(const glm::vec3& worldPos, float maxDist) {
+    clearSelection();
+    float bestDist = maxDist;
+    int bestIdx = -1;
+    for (int i = 0; i < static_cast<int>(spawns_.size()); i++) {
+        float dist = glm::length(spawns_[i].position - worldPos);
+        if (dist < bestDist) { bestDist = dist; bestIdx = i; }
+    }
+    if (bestIdx >= 0) {
+        selectedIdx_ = bestIdx;
+        spawns_[bestIdx].selected = true;
+    }
+    return bestIdx;
+}
+
+void NpcSpawner::clearSelection() {
+    if (selectedIdx_ >= 0 && selectedIdx_ < static_cast<int>(spawns_.size()))
+        spawns_[selectedIdx_].selected = false;
+    selectedIdx_ = -1;
+}
+
+CreatureSpawn* NpcSpawner::getSelected() {
+    if (selectedIdx_ < 0 || selectedIdx_ >= static_cast<int>(spawns_.size())) return nullptr;
+    return &spawns_[selectedIdx_];
+}
+
+bool NpcSpawner::saveToFile(const std::string& path) const {
+    auto dir = std::filesystem::path(path).parent_path();
+    if (!dir.empty()) std::filesystem::create_directories(dir);
+
+    std::ofstream f(path);
+    if (!f) { LOG_ERROR("Failed to write NPC file: ", path); return false; }
+
+    f << "[\n";
+    for (size_t i = 0; i < spawns_.size(); i++) {
+        const auto& s = spawns_[i];
+        f << "  {\n";
+        f << "    \"name\": \"" << s.name << "\",\n";
+        f << "    \"model\": \"" << s.modelPath << "\",\n";
+        f << "    \"displayId\": " << s.displayId << ",\n";
+        f << "    \"position\": [" << s.position.x << "," << s.position.y << "," << s.position.z << "],\n";
+        f << "    \"orientation\": " << s.orientation << ",\n";
+        f << "    \"level\": " << s.level << ",\n";
+        f << "    \"health\": " << s.health << ",\n";
+        f << "    \"mana\": " << s.mana << ",\n";
+        f << "    \"minDamage\": " << s.minDamage << ",\n";
+        f << "    \"maxDamage\": " << s.maxDamage << ",\n";
+        f << "    \"armor\": " << s.armor << ",\n";
+        f << "    \"faction\": " << s.faction << ",\n";
+        f << "    \"behavior\": " << static_cast<int>(s.behavior) << ",\n";
+        f << "    \"wanderRadius\": " << s.wanderRadius << ",\n";
+        f << "    \"aggroRadius\": " << s.aggroRadius << ",\n";
+        f << "    \"leashRadius\": " << s.leashRadius << ",\n";
+        f << "    \"respawnTimeMs\": " << s.respawnTimeMs << ",\n";
+        f << "    \"hostile\": " << (s.hostile ? "true" : "false") << ",\n";
+        f << "    \"questgiver\": " << (s.questgiver ? "true" : "false") << ",\n";
+        f << "    \"vendor\": " << (s.vendor ? "true" : "false") << ",\n";
+        f << "    \"flightmaster\": " << (s.flightmaster ? "true" : "false") << ",\n";
+        f << "    \"innkeeper\": " << (s.innkeeper ? "true" : "false") << ",\n";
+        f << "    \"patrol\": [";
+        for (size_t p = 0; p < s.patrolPath.size(); p++) {
+            f << "[" << s.patrolPath[p].position.x << "," << s.patrolPath[p].position.y
+              << "," << s.patrolPath[p].position.z << "," << s.patrolPath[p].waitTimeMs << "]";
+            if (p + 1 < s.patrolPath.size()) f << ",";
+        }
+        f << "]\n";
+        f << "  }" << (i + 1 < spawns_.size() ? "," : "") << "\n";
+    }
+    f << "]\n";
+
+    LOG_INFO("NPC spawns saved: ", path, " (", spawns_.size(), " creatures)");
+    return true;
+}
+
+bool NpcSpawner::loadFromFile(const std::string& path) {
+    // Simple JSON-ish parser for our format — full JSON parsing would need a library
+    LOG_INFO("NPC spawn loading not yet implemented for: ", path);
+    return false;
+}
+
+} // namespace editor
+} // namespace wowee