Decode portal wallpapers by content and simplify status bar

Detect wallpaper image formats from their contents so extensionless portal copies render on the desktop and lock screen. Preserve decode limits and cover extensionless files with regression tests.

Remove the Bluetooth icon from the status bar.

shell/ferese-lock/src/appearance.rs

@@ -169,6 +169,16 @@ fn account_picture(user: &str) -> Option<image::Handle> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    #[test]
+    fn portal_wallpaper_loads_without_a_filename_extension() {
+        let file = tempfile::NamedTempFile::new().unwrap();
+        ::image::RgbaImage::from_pixel(3, 2, ::image::Rgba([32, 80, 160, 255]))
+            .save_with_format(file.path(), ::image::ImageFormat::Png)
+            .unwrap();
+        assert!(load_wallpaper(file.path(), 0.).is_ok());
+        assert!(load_wallpaper(file.path(), 2.).is_ok());
+    }
+
     #[test]
     fn lock_options_share_shell_style_without_changing_security() {
         let directory = tempfile::tempdir().unwrap();
@@ -211,11 +221,22 @@ mod tests {
 }
 
 pub fn load_wallpaper(path: &std::path::Path, blur: f32) -> Result<image::Handle, String> {
-    let (width, height) = ::image::image_dimensions(path).map_err(|e| e.to_string())?;
+    use ::image::ImageDecoder;
+    let mut reader = ::image::ImageReader::open(path)
+        .map_err(|e| e.to_string())?
+        .with_guessed_format()
+        .map_err(|e| e.to_string())?;
+    let mut limits = ::image::Limits::default();
+    limits.max_alloc = Some(256 * 1024 * 1024);
+    reader.limits(limits);
+    let decoder = reader.into_decoder().map_err(|e| e.to_string())?;
+    let (width, height) = decoder.dimensions();
     if u64::from(width) * u64::from(height) * 4 > 256 * 1024 * 1024 {
         return Err("Lock wallpaper exceeds the decode limit".into());
     }
-    let pixels = ::image::open(path).map_err(|e| e.to_string())?.into_rgba8();
+    let pixels = ::image::DynamicImage::from_decoder(decoder)
+        .map_err(|e| e.to_string())?
+        .into_rgba8();
     let pixels = if blur > 0. {
         ::image::imageops::blur(&::image::imageops::thumbnail(&pixels, 640, 640), blur)
     } else {