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.hpp

@@ -0,0 +1,90 @@
+#pragma once
+
+#include <glm/glm.hpp>
+#include <string>
+#include <vector>
+#include <cstdint>
+
+namespace wowee {
+namespace editor {
+
+enum class CreatureBehavior {
+    Stationary,
+    Patrol,
+    Wander,
+    Scripted
+};
+
+struct PatrolPoint {
+    glm::vec3 position;
+    float waitTimeMs = 2000.0f;
+};
+
+struct CreatureSpawn {
+    uint32_t id = 0;
+    std::string name = "Creature";
+    std::string modelPath;
+    uint32_t displayId = 0;
+
+    // Position
+    glm::vec3 position{0};
+    float orientation = 0.0f; // degrees
+
+    // Stats
+    uint32_t level = 1;
+    uint32_t health = 100;
+    uint32_t mana = 0;
+    uint32_t minDamage = 5;
+    uint32_t maxDamage = 10;
+    uint32_t armor = 0;
+    uint32_t faction = 0; // 0 = neutral
+
+    // Behavior
+    CreatureBehavior behavior = CreatureBehavior::Stationary;
+    float wanderRadius = 10.0f;
+    float aggroRadius = 20.0f;
+    float leashRadius = 40.0f;
+    uint32_t respawnTimeMs = 300000;
+    std::vector<PatrolPoint> patrolPath;
+
+    // Flags
+    bool hostile = false;
+    bool questgiver = false;
+    bool vendor = false;
+    bool flightmaster = false;
+    bool innkeeper = false;
+
+    bool selected = false;
+};
+
+class NpcSpawner {
+public:
+    void placeCreature(const CreatureSpawn& spawn);
+    void removeCreature(int index);
+
+    int selectAt(const glm::vec3& worldPos, float maxDist = 30.0f);
+    void clearSelection();
+    CreatureSpawn* getSelected();
+    int getSelectedIndex() const { return selectedIdx_; }
+
+    const std::vector<CreatureSpawn>& getSpawns() const { return spawns_; }
+    std::vector<CreatureSpawn>& getSpawns() { return spawns_; }
+    size_t spawnCount() const { return spawns_.size(); }
+
+    // Serialize to/from JSON
+    bool saveToFile(const std::string& path) const;
+    bool loadFromFile(const std::string& path);
+
+    // Template creature for placement
+    CreatureSpawn& getTemplate() { return template_; }
+
+private:
+    uint32_t nextId();
+    std::vector<CreatureSpawn> spawns_;
+    int selectedIdx_ = -1;
+    uint32_t idCounter_ = 1;
+    CreatureSpawn template_;
+};
+
+} // namespace editor
+} // namespace wowee