fix: UITextInput focus and keyboard input - hitTest + dispatch handlers

Fixed three critical bugs preventing UITextInput from working:

1. **hitTest() missing textinput handler**: The hit test function only checked
   for button, slider, and checkbox types. Clicks on text input fields were
   never detected.

   FIX: Added textinput case to hitTest() in UIContext.cpp

2. **dispatchMouseButton() missing textinput handler**: Even if hit test worked,
   mouse button events were not dispatched to text input widgets.

   FIX: Added textinput case to dispatchMouseButton() in UIContext.cpp

3. **Keyboard event collision**: SDL_KEYDOWN was publishing events for printable
   characters with char=0, which were rejected by UITextInput. Printable chars
   should only come from SDL_TEXTINPUT.

   FIX: Only publish SDL_KEYDOWN for special keys (Backspace, Delete, arrows, etc.)
   Printable characters come exclusively from SDL_TEXTINPUT events.

Changes:
- UIContext.cpp: Added textinput handlers to hitTest() and dispatchMouseButton()
- UITextInput.cpp: Added debug logging for gainFocus() and render()
- UIModule.cpp: Added debug logging for widget clicks
- test_ui_showcase.cpp: Fixed keyboard event handling (KEYDOWN vs TEXTINPUT)

Tested: Text input now gains focus (border turns blue), accepts keyboard input,
and displays typed text correctly.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

modules/UIModule/Core/UIContext.cpp

@@ -3,6 +3,7 @@
 #include "../Widgets/UIButton.h"
 #include "../Widgets/UISlider.h"
 #include "../Widgets/UICheckbox.h"
+#include "../Widgets/UITextInput.h"
 #include <spdlog/spdlog.h>
 
 namespace grove {
@@ -52,6 +53,12 @@ UIWidget* hitTest(UIWidget* widget, float x, float y) {
             return widget;
         }
     }
+    else if (type == "textinput") {
+        UITextInput* textInput = static_cast<UITextInput*>(widget);
+        if (textInput->containsPoint(x, y)) {
+            return widget;
+        }
+    }
 
     return nullptr;
 }
@@ -135,6 +142,14 @@ UIWidget* dispatchMouseButton(UIWidget* widget, UIContext& ctx, int button, bool
             return target;  // Return for value_changed publishing
         }
     }
+    else if (type == "textinput") {
+        UITextInput* textInput = static_cast<UITextInput*>(target);
+        handled = textInput->onMouseButton(button, pressed, ctx.mouseX, ctx.mouseY);
+
+        if (handled) {
+            return target;  // Return for focus handling in UIModule
+        }
+    }
 
     return handled ? target : nullptr;
 }

modules/UIModule/UIModule.cpp

@@ -208,6 +208,9 @@ void UIModule::updateUI(float deltaTime) {
             // Publish type-specific events
             std::string widgetType = clickedWidget->getType();
 
+            m_logger->info("🖱️ Widget clicked: id='{}', type='{}', mousePressed={}",
+                clickedWidget->id, widgetType, m_context->mousePressed);
+
             // Handle focus for text inputs
             if (widgetType == "textinput" && m_context->mousePressed) {
                 UITextInput* textInput = static_cast<UITextInput*>(clickedWidget);

modules/UIModule/Widgets/UITextInput.cpp

@@ -3,6 +3,7 @@
 #include "../Rendering/UIRenderer.h"
 #include <algorithm>
 #include <cctype>
+#include <spdlog/spdlog.h>
 
 namespace grove {
 
@@ -63,6 +64,14 @@ void UITextInput::render(UIRenderer& renderer) {
     // Render border
     int borderLayer = renderer.nextLayer();
     uint32_t borderColor = isFocused ? style.focusBorderColor : style.borderColor;
+
+    static int renderCount = 0;
+    if (renderCount < 5) {
+        spdlog::info("🎨 UITextInput '{}' render: isFocused={}, borderColor=0x{:08X} (focus=0x{:08X}, normal=0x{:08X})",
+            id, isFocused, borderColor, style.focusBorderColor, style.borderColor);
+        renderCount++;
+    }
+
     renderer.updateRect(m_borderRenderId, absX, absY + height - style.borderWidth,
                        width, style.borderWidth, borderColor, borderLayer);
 
@@ -199,6 +208,7 @@ void UITextInput::gainFocus() {
         isFocused = true;
         cursorBlinkTimer = 0.0f;
         cursorVisible = true;
+        spdlog::info("🎯 UITextInput '{}' gainFocus() called - isFocused={}", id, isFocused);
     }
 }
 

tests/visual/test_ui_showcase.cpp

@@ -494,14 +494,24 @@ public:
             m_gameIO->publish("input:mouse:wheel", std::move(msg));
         }
         else if (e.type == SDL_KEYDOWN) {
+            // Only publish special keys (non-printable), printable chars come from SDL_TEXTINPUT
+            int keyCode = e.key.keysym.sym;
+            bool isSpecialKey = (keyCode == SDLK_BACKSPACE || keyCode == SDLK_DELETE ||
+                                keyCode == SDLK_RETURN || keyCode == SDLK_LEFT ||
+                                keyCode == SDLK_RIGHT || keyCode == SDLK_HOME ||
+                                keyCode == SDLK_END || keyCode == SDLK_UP ||
+                                keyCode == SDLK_DOWN || keyCode == SDLK_TAB);
+
+            if (isSpecialKey) {
                 auto msg = std::make_unique<JsonDataNode>("key");
-            msg->setInt("keyCode", e.key.keysym.sym);
-            msg->setInt("scancode", e.key.keysym.scancode);
+                msg->setInt("keyCode", keyCode);
                 msg->setBool("pressed", true);
                 msg->setInt("char", 0);
                 m_gameIO->publish("input:keyboard", std::move(msg));
             }
+        }
         else if (e.type == SDL_TEXTINPUT) {
+            // Printable characters come here
             auto msg = std::make_unique<JsonDataNode>("key");
             msg->setInt("keyCode", 0);
             msg->setBool("pressed", true);