Keep the written image name in update suggestions

docker.io/calico/node was suggested as calico/node, which reads as a
different image and would rewrite the workload's reference.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/crates/domain/src/image.rs

@@ -7,6 +7,8 @@ pub struct ImageRef {
     pub registry: String,
     pub repository: String,
     pub tag: String,
+    /// The name exactly as it was written, so a suggestion keeps the original spelling.
+    pub name: String,
 }
 
 impl ImageRef {
@@ -34,6 +36,7 @@ impl ImageRef {
             registry,
             repository,
             tag,
+            name: head.to_string(),
         })
     }