feat(editor): export NPC/M2 model textures as PNG with the zone

TextureExporter::collectUsedTextures only picked up terrain textures, so
exported zones were missing every texture referenced by NPC creature models
and placed M2 doodads. Added collectM2Textures() and unified the export
collection to include terrain + all referenced M2 paths, so the rendered
zone is fully self-contained in the PNG/WOM open formats.

tools/editor/editor_app.cpp

@@ -1080,12 +1080,31 @@ void EditorApp::exportZone(const std::string& outputDir) {
             LOG_INFO("Converted ", convertedWMOs.size(), " WMO buildings to WOB");
     }
 
-    // Export used textures as PNG (open format replacement for BLP)
-    auto usedTextures = TextureExporter::collectUsedTextures(terrain_);
-    if (!usedTextures.empty()) {
-        int exported = TextureExporter::exportTexturesAsPng(
-            assetManager_.get(), usedTextures, base + "/textures");
-        LOG_INFO("Exported ", exported, " textures as PNG");
+    // Export used textures as PNG (open format replacement for BLP).
+    // Includes terrain textures plus textures referenced by every placed M2/NPC model
+    // so the exported zone has every texture it needs to render without game data.
+    std::vector<std::string> usedTextures;
+    {
+        std::unordered_set<std::string> uniq;
+        for (auto& t : TextureExporter::collectUsedTextures(terrain_)) uniq.insert(std::move(t));
+        std::unordered_set<std::string> visitedM2;
+        auto addM2Tex = [&](const std::string& m2Path) {
+            if (m2Path.empty() || !visitedM2.insert(m2Path).second) return;
+            for (auto& t : TextureExporter::collectM2Textures(assetManager_.get(), m2Path))
+                uniq.insert(std::move(t));
+        };
+        for (const auto& obj : objectPlacer_.getObjects()) {
+            if (obj.type == PlaceableType::M2) addM2Tex(obj.path);
+        }
+        for (const auto& npc : npcSpawner_.getSpawns()) addM2Tex(npc.modelPath);
+
+        usedTextures.assign(uniq.begin(), uniq.end());
+        std::sort(usedTextures.begin(), usedTextures.end());
+        if (!usedTextures.empty()) {
+            int exported = TextureExporter::exportTexturesAsPng(
+                assetManager_.get(), usedTextures, base + "/textures");
+            LOG_INFO("Exported ", exported, " textures as PNG (terrain + ", visitedM2.size(), " M2s)");
+        }
     }
 
     // Export zone-relevant DBCs as JSON (open format replacement for DBC)

tools/editor/texture_exporter.cpp

@@ -1,6 +1,7 @@
 #include "texture_exporter.hpp"
 #include "pipeline/asset_manager.hpp"
 #include "pipeline/blp_loader.hpp"
+#include "pipeline/m2_loader.hpp"
 #include "core/logger.hpp"
 #include <filesystem>
 #include <algorithm>
@@ -20,6 +21,30 @@ std::vector<std::string> TextureExporter::collectUsedTextures(const pipeline::AD
     return result;
 }
 
+std::vector<std::string> TextureExporter::collectM2Textures(pipeline::AssetManager* am,
+                                                              const std::string& m2Path) {
+    std::vector<std::string> out;
+    if (!am || m2Path.empty()) return out;
+
+    auto data = am->readFile(m2Path);
+    if (data.empty()) return out;
+    auto m2 = pipeline::M2Loader::load(data);
+    // Skin file holds geometry but textures live in the M2 header itself.
+    // Even if isValid() is false (no skin loaded), the texture list is populated.
+
+    std::unordered_set<std::string> unique;
+    for (const auto& tex : m2.textures) {
+        if (tex.filename.empty()) continue;
+        std::string p = tex.filename;
+        std::transform(p.begin(), p.end(), p.begin(),
+                       [](unsigned char c) { return std::tolower(c); });
+        unique.insert(p);
+    }
+    out.assign(unique.begin(), unique.end());
+    std::sort(out.begin(), out.end());
+    return out;
+}
+
 int TextureExporter::exportTexturesAsPng(pipeline::AssetManager* am,
                                           const std::vector<std::string>& texturePaths,
                                           const std::string& outputDir) {

tools/editor/texture_exporter.hpp

@@ -15,6 +15,11 @@ public:
     // Collect all texture paths referenced by the terrain
     static std::vector<std::string> collectUsedTextures(const pipeline::ADTTerrain& terrain);
 
+    // Collect all texture paths referenced by an M2 model (loads the M2 from `am`).
+    // Returns lowercased game paths (e.g. "creature\\foo\\foo.blp"). Empty if M2 not found.
+    static std::vector<std::string> collectM2Textures(pipeline::AssetManager* am,
+                                                       const std::string& m2Path);
+
     // Export all used textures as PNG to an output directory
     // Returns count of successfully exported textures
     static int exportTexturesAsPng(pipeline::AssetManager* am,