feat(editor): auto-save settings UI, multi-tile zone.json, toast notify

- Auto-save toast notification when auto-save fires
- Edit > Auto-Save Settings: enable/disable toggle, interval slider
  (60-900s), countdown timer display
- Zone manifest now scans output directory for all exported ADT tiles
  and includes them in zone.json (adjacent tiles no longer orphaned)
- Auto-save interval and enabled state exposed via EditorApp accessors

tools/editor/editor_app.cpp

@@ -101,6 +101,7 @@ void EditorApp::run() {
             if (autoSaveTimer_ >= autoSaveInterval_) {
                 autoSaveTimer_ = 0.0f;
                 quickSave();
+                showToast("Auto-saved", 2.0f);
                 LOG_INFO("Auto-saved zone");
             }
         }
@@ -969,10 +970,28 @@ void EditorApp::exportZone(const std::string& outputDir) {
     }
 
     // Write zone manifest (for client loading)
+    // Scan output directory for all exported tiles (includes adjacent tiles)
     ZoneManifest manifest;
     manifest.mapName = loadedMap_;
     manifest.displayName = loadedMap_;
     manifest.tiles.push_back({loadedTileX_, loadedTileY_});
+    namespace fs = std::filesystem;
+    if (fs::exists(base)) {
+        for (auto& entry : fs::directory_iterator(base)) {
+            if (entry.path().extension() != ".adt") continue;
+            std::string stem = entry.path().stem().string();
+            auto lastU = stem.rfind('_');
+            auto prevU = stem.rfind('_', lastU - 1);
+            if (lastU != std::string::npos && prevU != std::string::npos) {
+                try {
+                    int tx = std::stoi(stem.substr(prevU + 1, lastU - prevU - 1));
+                    int ty = std::stoi(stem.substr(lastU + 1));
+                    if (tx == loadedTileX_ && ty == loadedTileY_) continue;
+                    manifest.tiles.push_back({tx, ty});
+                } catch (...) {}
+            }
+        }
+    }
     manifest.hasCreatures = (npcSpawner_.spawnCount() > 0);
     manifest.baseHeight = terrain_.chunks[0].position[2];
     manifest.save(base + "/zone.json");

tools/editor/editor_app.hpp

@@ -149,6 +149,11 @@ public:
     void showToast(const std::string& msg, float duration = 3.0f);
     const std::vector<Toast>& getToasts() const { return toasts_; }
     const std::vector<RecentZone>& getRecentZones() const { return recentZones_; }
+    bool isAutoSaveEnabled() const { return autoSaveEnabled_; }
+    void setAutoSaveEnabled(bool v) { autoSaveEnabled_ = v; }
+    float getAutoSaveInterval() const { return autoSaveInterval_; }
+    void setAutoSaveInterval(float s) { autoSaveInterval_ = std::clamp(s, 60.0f, 900.0f); }
+    float getAutoSaveTimeRemaining() const { return autoSaveInterval_ - autoSaveTimer_; }
     void updateToasts(float dt);
 private:
     size_t lastObjCount_ = 0;

tools/editor/editor_ui.cpp

@@ -375,6 +375,17 @@ void EditorUI::renderMenuBar(EditorApp& app) {
             auto& te = app.getTerrainEditor();
             if (ImGui::MenuItem("Undo", "Ctrl+Z", false, te.history().canUndo())) te.undo();
             if (ImGui::MenuItem("Redo", "Ctrl+Shift+Z", false, te.history().canRedo())) te.redo();
+            ImGui::Separator();
+            if (ImGui::BeginMenu("Auto-Save Settings")) {
+                bool enabled = app.isAutoSaveEnabled();
+                if (ImGui::Checkbox("Enabled", &enabled)) app.setAutoSaveEnabled(enabled);
+                float interval = app.getAutoSaveInterval();
+                if (ImGui::SliderFloat("Interval (sec)", &interval, 60.0f, 900.0f, "%.0fs"))
+                    app.setAutoSaveInterval(interval);
+                ImGui::TextColored(ImVec4(0.6f, 0.6f, 0.6f, 1),
+                    "Next in: %.0fs", app.getAutoSaveTimeRemaining());
+                ImGui::EndMenu();
+            }
             ImGui::EndMenu();
         }
         if (ImGui::BeginMenu("View")) {