feat(server): add tracing spans and caching to archive and blame services

- Add tracing spans with repo labels for archive and blame operations
- Implement caching for archive list entries when using OID selectors
- Implement caching for blame operations when using OID selectors
- Add detailed

pack/pack_objects.rs

@@ -18,6 +18,10 @@ impl GitBare {
     ) -> Result<ReceiverStream<Result<PackfileChunk, tonic::Status>>, tonic::Status> {
         let bare_dir = self.bare_dir.clone();
         let bare_dir_str = bare_dir.to_string_lossy().into_owned();
+        tracing::info!(
+            repo = %bare_dir_str,
+            "spawning git pack-objects subprocess"
+        );
 
         let (tx, rx) = tokio::sync::mpsc::channel(8);