feat: Improve FSR2 UI with dropdown quality mode and conditional FSR sharpness

- Convert FSR2 quality mode from number input to dropdown with 4 options
- Disable and grey out FSR sharpness slider when FSR2 is selected
- Add proper enum-based settings for FSR2 quality modes
- Update both Vulkan and OpenGL FSR2 implementations
- Connect UI state changes automatically

Provides better UX by using appropriate controls and preventing confusion
between FSR 1.0 and FSR 2.0 sharpening options.

Signed-off-by: Zephyron <zephyron@citron-emu.org>

src/common/settings.h

@@ -348,15 +348,15 @@ struct Values {
                                                        true,
                                                        true};
 
-    SwitchableSetting<int, true> fsr2_quality_mode{linkage,
-                                                   2,  // Performance by default
-                                                   0,  // Quality
-                                                   3,  // Ultra Performance
-                                                   "fsr2_quality_mode",
-                                                   Category::Renderer,
-                                                   Specialization::Default,
-                                                   true,
-                                                   true};
+    SwitchableSetting<FSR2QualityMode, true> fsr2_quality_mode{linkage,
+                                                               FSR2QualityMode::Performance,  // Performance by default
+                                                               FSR2QualityMode::Quality,
+                                                               FSR2QualityMode::UltraPerformance,
+                                                               "fsr2_quality_mode",
+                                                               Category::Renderer,
+                                                               Specialization::Default,
+                                                               true,
+                                                               true};
 
     SwitchableSetting<u8, false> bg_red{
         linkage, 0, "bg_red", Category::Renderer, Specialization::Default, true, true};

src/common/settings_enums.h

@@ -151,6 +151,8 @@ ENUM(ScalingFilter, NearestNeighbor, Bilinear, Bicubic, Gaussian, ScaleForce, Fs
 
 ENUM(AntiAliasing, None, Fxaa, Smaa, MaxEnum);
 
+ENUM(FSR2QualityMode, Quality, Balanced, Performance, UltraPerformance);
+
 ENUM(AspectRatio, R16_9, R4_3, R21_9, R16_10, R32_9, Stretch);
 
 ENUM(ConsoleMode, Handheld, Docked);