feat: integrate keybinding customization UI into Settings window

- Extended KeybindingManager enum with TOGGLE_GUILD_ROSTER (O) and
  TOGGLE_DUNGEON_FINDER (J) to replace hard-coded key checks
- Added Controls tab in Settings UI for rebinding all 10 customizable actions
- Implemented real-time key capture and binding with visual feedback
- Integrated keybinding persistence with main settings.cfg file
- Replaced hard-coded O key (Guild Roster) and I key (Dungeon Finder) checks
  with KeybindingManager::isActionPressed() calls
- Added Reset to Defaults button for restoring original keybindings

include/ui/game_screen.hpp

@@ -8,6 +8,7 @@
 #include "ui/quest_log_screen.hpp"
 #include "ui/spellbook_screen.hpp"
 #include "ui/talent_screen.hpp"
+#include "ui/keybinding_manager.hpp"
 #include <vulkan/vulkan.h>
 #include <imgui.h>
 #include <string>
@@ -111,6 +112,10 @@ private:
     bool pendingMinimapNpcDots = false;
     bool pendingSeparateBags = true;
     bool pendingAutoLoot = false;
+
+    // Keybinding customization
+    int pendingRebindAction = -1;  // -1 = not rebinding, otherwise action index
+    bool awaitingKeyPress = false;
     bool pendingUseOriginalSoundtrack = true;
     bool pendingShowActionBar2 = true;   // Show second action bar above main bar
     float pendingActionBar2OffsetX = 0.0f;  // Horizontal offset from default center position

include/ui/keybinding_manager.hpp

@@ -23,6 +23,8 @@ public:
         TOGGLE_MINIMAP,
         TOGGLE_SETTINGS,
         TOGGLE_CHAT,
+        TOGGLE_GUILD_ROSTER,
+        TOGGLE_DUNGEON_FINDER,
         ACTION_COUNT
     };