Implement rendering of images with data urls in markdown (#30322)

Fixes #28266

![Screenshot 2025-05-08 at 5 08
21 PM](https://github.com/user-attachments/assets/774d2dde-3f2d-466c-8eb1-c67badbd89e4)

Release Notes:

- Added support for rendering images with data URLs in markdown. This
can show up in hover documentation provided by language servers.

Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>

crates/agent/src/context.rs

@@ -754,11 +754,11 @@ pub enum ImageStatus {
 
 impl ImageContext {
     pub fn eq_for_key(&self, other: &Self) -> bool {
-        self.original_image.id == other.original_image.id
+        self.original_image.id() == other.original_image.id()
     }
 
     pub fn hash_for_key<H: Hasher>(&self, state: &mut H) {
-        self.original_image.id.hash(state);
+        self.original_image.id().hash(state);
     }
 
     pub fn image(&self) -> Option<LanguageModelImage> {