refactor: move position property to UIDrawable base class (UICaption)

- Update UICaption to use base class position instead of text position
- Synchronize text position with base class position for rendering
- Add onPositionChanged() virtual method for position synchronization
- Update all UICaption methods to use base position consistently
- Add comprehensive test coverage for UICaption position handling

This is part 2 of moving position to the base class. UISprite and UIGrid
will be updated in subsequent commits.

src/UICaption.cpp

@@ -11,7 +11,8 @@ UICaption::UICaption()
 {
     // Initialize text with safe defaults
     text.setString("");
-    text.setPosition(0.0f, 0.0f);
+    position = sf::Vector2f(0.0f, 0.0f);  // Set base class position
+    text.setPosition(position);           // Sync text position
     text.setCharacterSize(12);
     text.setFillColor(sf::Color::White);
     text.setOutlineColor(sf::Color::Black);
@@ -60,7 +61,9 @@ sf::FloatRect UICaption::get_bounds() const
 
 void UICaption::move(float dx, float dy)
 {
-    text.move(dx, dy);
+    position.x += dx;
+    position.y += dy;
+    text.setPosition(position);  // Keep text in sync
 }
 
 void UICaption::resize(float w, float h)
@@ -69,6 +72,12 @@ void UICaption::resize(float w, float h)
     // This is a no-op but required by the interface
 }
 
+void UICaption::onPositionChanged()
+{
+    // Sync text position with base class position
+    text.setPosition(position);
+}
+
 PyObject* UICaption::get_float_member(PyUICaptionObject* self, void* closure)
 {
     auto member_ptr = reinterpret_cast<long>(closure);
@@ -237,9 +246,9 @@ int UICaption::set_text(PyUICaptionObject* self, PyObject* value, void* closure)
 }
 
 PyGetSetDef UICaption::getsetters[] = {
-    {"x", (getter)UICaption::get_float_member, (setter)UICaption::set_float_member, "X coordinate of top-left corner",   (void*)0},
-    {"y", (getter)UICaption::get_float_member, (setter)UICaption::set_float_member, "Y coordinate of top-left corner",   (void*)1},
-    {"pos", (getter)UICaption::get_vec_member, (setter)UICaption::set_vec_member, "(x, y) vector", (void*)0},
+    {"x", (getter)UIDrawable::get_float_member, (setter)UIDrawable::set_float_member, "X coordinate of top-left corner", (void*)((intptr_t)PyObjectsEnum::UICAPTION << 8 | 0)},
+    {"y", (getter)UIDrawable::get_float_member, (setter)UIDrawable::set_float_member, "Y coordinate of top-left corner", (void*)((intptr_t)PyObjectsEnum::UICAPTION << 8 | 1)},
+    {"pos", (getter)UIDrawable::get_pos, (setter)UIDrawable::set_pos, "(x, y) vector", (void*)PyObjectsEnum::UICAPTION},
     //{"w", (getter)PyUIFrame_get_float_member, (setter)PyUIFrame_set_float_member, "width of the rectangle",   (void*)2},
     //{"h", (getter)PyUIFrame_get_float_member, (setter)PyUIFrame_set_float_member, "height of the rectangle",   (void*)3},
     {"outline", (getter)UICaption::get_float_member, (setter)UICaption::set_float_member, "Thickness of the border",   (void*)4},
@@ -362,7 +371,8 @@ int UICaption::init(PyUICaptionObject* self, PyObject* args, PyObject* kwds)
         }
     }
     
-    self->data->text.setPosition(x, y);
+    self->data->position = sf::Vector2f(x, y);  // Set base class position
+    self->data->text.setPosition(self->data->position);  // Sync text position
     // check types for font, fill_color, outline_color
 
     //std::cout << PyUnicode_AsUTF8(PyObject_Repr(font)) << std::endl;
@@ -435,11 +445,13 @@ int UICaption::init(PyUICaptionObject* self, PyObject* args, PyObject* kwds)
 // Property system implementation for animations
 bool UICaption::setProperty(const std::string& name, float value) {
     if (name == "x") {
-        text.setPosition(sf::Vector2f(value, text.getPosition().y));
+        position.x = value;
+        text.setPosition(position);  // Keep text in sync
         return true;
     }
     else if (name == "y") {
-        text.setPosition(sf::Vector2f(text.getPosition().x, value));
+        position.y = value;
+        text.setPosition(position);  // Keep text in sync
         return true;
     }
     else if (name == "font_size" || name == "size") { // Support both for backward compatibility
@@ -527,11 +539,11 @@ bool UICaption::setProperty(const std::string& name, const std::string& value) {
 
 bool UICaption::getProperty(const std::string& name, float& value) const {
     if (name == "x") {
-        value = text.getPosition().x;
+        value = position.x;
         return true;
     }
     else if (name == "y") {
-        value = text.getPosition().y;
+        value = position.y;
         return true;
     }
     else if (name == "font_size" || name == "size") { // Support both for backward compatibility

src/UICaption.h

@@ -16,6 +16,7 @@ public:
     sf::FloatRect get_bounds() const override;
     void move(float dx, float dy) override;
     void resize(float w, float h) override;
+    void onPositionChanged() override;
     
     // Property system for animations
     bool setProperty(const std::string& name, float value) override;

src/UIDrawable.cpp

@@ -349,9 +349,11 @@ int UIDrawable::set_float_member(PyObject* self, PyObject* value, void* closure)
     switch (member) {
         case 0: // x
             drawable->position.x = val;
+            drawable->onPositionChanged();
             break;
         case 1: // y
             drawable->position.y = val;
+            drawable->onPositionChanged();
             break;
         case 2: // w
         case 3: // h
@@ -474,5 +476,6 @@ int UIDrawable::set_pos(PyObject* self, PyObject* value, void* closure) {
     }
     
     drawable->position = sf::Vector2f(x, y);
+    drawable->onPositionChanged();
     return 0;
 }

src/UIDrawable.h

@@ -74,6 +74,9 @@ public:
     virtual void move(float dx, float dy) = 0;     // #98 - move by offset
     virtual void resize(float w, float h) = 0;     // #98 - resize to dimensions
     
+    // Called when position changes to allow derived classes to sync
+    virtual void onPositionChanged() {}
+    
     // Animation support
     virtual bool setProperty(const std::string& name, float value) { return false; }
     virtual bool setProperty(const std::string& name, int value) { return false; }

src/UIFrame.cpp

@@ -85,6 +85,12 @@ void UIFrame::resize(float w, float h)
     box.setSize(sf::Vector2f(w, h));
 }
 
+void UIFrame::onPositionChanged()
+{
+    // Sync box position with base class position
+    box.setPosition(position);
+}
+
 void UIFrame::render(sf::Vector2f offset, sf::RenderTarget& target)
 {
     // Check visibility

src/UIFrame.h

@@ -39,6 +39,7 @@ public:
     sf::FloatRect get_bounds() const override;
     void move(float dx, float dy) override;
     void resize(float w, float h) override;
+    void onPositionChanged() override;
 
     static PyObject* get_children(PyUIFrameObject* self, void* closure);