Fix clear color in CompositingSpace::Srgb (#23963)

# Objective

Split off from #23803, Fix `ClearColor` with `CompositingSpace::Srgb`.

## Solution

Convert clear color to Srgb

## Testing

Code from
#9213 (comment):
```rs
//!

use bevy::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .insert_resource(ClearColor(Color::srgba(0., 0.5, 0., 1.)))
        .add_systems(Startup, |mut commands: Commands| {
            commands.spawn((Camera2d, CompositingSpace::Srgb));

            commands.spawn((
                Sprite::from_color(Color::WHITE.with_alpha(0.5), Vec2::new(512., 512.)),
                Transform::from_xyz(-256., 0., 0.),
            ));

            commands.spawn((
                Sprite::from_color(Color::BLACK.with_alpha(0.5), Vec2::new(512., 512.)),
                Transform::from_xyz(256., 0., 0.),
            ));
        })
        .run();
}

```

Before:
<img width="1410" height="878" alt="屏幕截图_20260414_120259"
src="https://github.com/user-attachments/assets/199e2832-d0ba-46fe-835a-8775c2a4adc6"
/>

After:
<img width="1410" height="878" alt="屏幕截图_20260414_115624"
src="https://github.com/user-attachments/assets/f4b26170-3a78-44f1-917d-8f061da83ad5"
/>

Author: beicause

crates/bevy_camera/src/components.rs

@@ -95,8 +95,8 @@ pub enum CompositingSpace {
     /// Gamma-encoded blending. Matches most image editors. Uses default sRGB target.
     #[default]
     Srgb,
-    /// Linear light blending. Physically correct. Requires [`Hdr`].
+    /// Linear light blending. Physically correct.
     Linear,
-    /// Perceptually uniform blending. Often smoother gradients. Requires [`Hdr`].
+    /// Perceptually uniform blending. Often smoother gradients. Requires [`Hdr`] because its value can be outside [0, 1].
     Oklab,
 }

crates/bevy_color/src/srgba.rs

@@ -415,6 +415,18 @@ impl From<Srgba> for Xyza {
     }
 }
 
+#[cfg(feature = "wgpu-types")]
+impl From<Srgba> for wgpu_types::Color {
+    fn from(color: Srgba) -> Self {
+        wgpu_types::Color {
+            r: color.red as f64,
+            g: color.green as f64,
+            b: color.blue as f64,
+            a: color.alpha as f64,
+        }
+    }
+}
+
 /// Error returned if a hex string could not be parsed as a color.
 #[derive(Debug, Error, PartialEq, Eq)]
 pub enum HexColorError {

crates/bevy_render/src/view/mod.rs

@@ -26,7 +26,7 @@ use crate::{
 };
 use alloc::sync::{Arc, Weak};
 use bevy_app::{App, Plugin};
-use bevy_color::{LinearRgba, Oklaba};
+use bevy_color::{LinearRgba, Oklaba, Srgba};
 use bevy_derive::{Deref, DerefMut};
 use bevy_ecs::prelude::*;
 use bevy_image::ToExtents;
@@ -1177,19 +1177,13 @@ pub fn prepare_view_targets(
         };
 
         // Convert clear color to the format expected by the main texture
-        let converted_clear_color: Option<WgpuColor> = clear_color.map(|color| {
-            let linear: LinearRgba = color.into();
-            if camera
-                .compositing_space
-                .is_some_and(|s| s == CompositingSpace::Oklab)
-            {
-                // Main texture stores Oklab; convert linear RGB to Oklab for correct clear
-                let oklab: Oklaba = linear.into();
-                oklab.into()
-            } else {
-                linear.into()
-            }
-        });
+        let converted_clear_color: Option<WgpuColor> =
+            clear_color.map(|color| match camera.compositing_space {
+                // If main texture stores Oklab or Srgb, convert Color to it for correct clear.
+                Some(CompositingSpace::Oklab) => Oklaba::from(color).into(),
+                Some(CompositingSpace::Srgb) => Srgba::from(color).into(),
+                Some(CompositingSpace::Linear) | None => LinearRgba::from(color).into(),
+            });
 
         let key: MainTextureKey = (
             camera.target.clone(),