feat(editor): scroll wheel zoom, clickable minimap navigation

- Scroll wheel now zooms camera (moves along look direction) instead
  of adjusting speed. Much more intuitive for terrain editing.
- Shift+scroll adjusts camera speed (old behavior preserved)
- Click on minimap to teleport camera to that location on the terrain
- Zoom speed scales with current camera speed for consistent feel

tools/editor/editor_app.cpp

@@ -382,7 +382,7 @@ void EditorApp::processEvents() {
         }
 
         if (event.type == SDL_MOUSEWHEEL && !io.WantCaptureMouse)
-            camera_.processMouseWheel(event.wheel.y);
+            camera_.processMouseWheel(event.wheel.y, (SDL_GetModState() & KMOD_SHIFT) != 0);
     }
 }
 

tools/editor/editor_camera.cpp

@@ -43,8 +43,14 @@ void EditorCamera::processMouseMotion(int dx, int dy) {
     camera_.setRotation(yaw_, pitch_);
 }
 
-void EditorCamera::processMouseWheel(float delta) {
-    speed_ = std::clamp(speed_ + delta * 20.0f, 10.0f, 2000.0f);
+void EditorCamera::processMouseWheel(float delta, bool shiftHeld) {
+    if (shiftHeld) {
+        speed_ = std::clamp(speed_ + delta * 20.0f, 10.0f, 2000.0f);
+    } else {
+        glm::vec3 pos = camera_.getPosition();
+        pos += camera_.getForward() * delta * speed_ * 0.3f;
+        camera_.setPosition(pos);
+    }
 }
 
 void EditorCamera::processKeyEvent(const SDL_KeyboardEvent& event) {

tools/editor/editor_camera.hpp

@@ -13,7 +13,7 @@ public:
 
     void update(float deltaTime);
     void processMouseMotion(int dx, int dy);
-    void processMouseWheel(float delta);
+    void processMouseWheel(float delta, bool shiftHeld);
     void processKeyEvent(const SDL_KeyboardEvent& event);
     void processMouseButton(const SDL_MouseButtonEvent& event);
 

tools/editor/editor_ui.cpp

@@ -1134,6 +1134,19 @@ void EditorUI::renderMinimap(EditorApp& app) {
         }
 
         ImGui::Dummy(ImVec2(avail.x, 16 * cellH));
+        // Click minimap to move camera
+        if (ImGui::IsWindowHovered() && ImGui::IsMouseClicked(0)) {
+            ImVec2 mousePos = ImGui::GetMousePos();
+            float mu = (mousePos.y - origin.y) / (16 * cellH);
+            float mv = (mousePos.x - origin.x) / avail.x;
+            if (mu >= 0 && mu <= 1 && mv >= 0 && mv <= 1) {
+                float wx = tileNW_X - mu * 533.33333f;
+                float wy = tileNW_Y - mv * 533.33333f;
+                app.getEditorCamera().setPosition(glm::vec3(wx, wy,
+                    app.getEditorCamera().getCamera().getPosition().z));
+            }
+        }
+
         // Camera indicator as white cross
         auto camPos = app.getEditorCamera().getCamera().getPosition();
         float camU = (tileNW_X - camPos.x) / 533.33333f;