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

commit/compare_commits.rs

@@ -1,10 +1,8 @@
 use crate::bare::GitBare;
+use crate::commit::list_commits::read_commit_from_repo;
 use crate::diff::get_diff_stats::diff_stats_for_range;
 use crate::error::{GitError, GitResult};
-use crate::paginate;
-use crate::pb::{
-    CommitStats, CompareCommitsRequest, CompareCommitsResponse, GetCommitRequest, object_selector,
-};
+use crate::pb::{CommitStats, CompareCommitsRequest, CompareCommitsResponse, object_selector};
 
 impl GitBare {
     pub fn compare_commits(
@@ -35,17 +33,66 @@ impl GitBare {
         } else {
             format!("{base}...{head}")
         };
-        let mut args = vec![
+
+        // Build base rev-list args
+        let mut base_args = vec![
             "--git-dir".to_string(),
             self.bare_dir.to_string_lossy().into_owned(),
             "rev-list".into(),
         ];
         if request.first_parent {
-            args.push("--first-parent".into());
+            base_args.push("--first-parent".into());
         }
-        args.push(range);
+        base_args.push(range);
 
-        let rev_list = duct::cmd("git", &args)
+        // 1. Total count
+        let total = {
+            let mut args = base_args.clone();
+            // Insert after "rev-list" (index 2)
+            args.insert(3, "--count".into());
+            let result = duct::cmd("git", &args)
+                .stdout_capture()
+                .stderr_capture()
+                .unchecked()
+                .run()?;
+            if !result.status.success() {
+                return Err(GitError::CommandFailed {
+                    status_code: result.status.code(),
+                    stderr: String::from_utf8_lossy(&result.stderr).into_owned(),
+                });
+            }
+            String::from_utf8_lossy(&result.stdout)
+                .trim()
+                .parse::<usize>()
+                .unwrap_or(0)
+        };
+
+        // 2. Git-side pagination
+        let page_size = request
+            .pagination
+            .as_ref()
+            .map(|p| p.page_size as usize)
+            .unwrap_or(total.max(1))
+            .max(1);
+        let start_offset = request
+            .pagination
+            .as_ref()
+            .and_then(|p| {
+                if p.page_token.is_empty() {
+                    None
+                } else {
+                    p.page_token.parse::<usize>().ok()
+                }
+            })
+            .unwrap_or(0)
+            .min(total);
+
+        let mut fetch_args = base_args;
+        // Insert after "rev-list" (index 2)
+        fetch_args.insert(3, format!("--skip={start_offset}"));
+        fetch_args.insert(4, format!("-n{page_size}"));
+
+        let rev_list = duct::cmd("git", &fetch_args)
             .stdout_capture()
             .stderr_capture()
             .unchecked()
@@ -57,28 +104,31 @@ impl GitBare {
             });
         }
 
-        let ids = String::from_utf8_lossy(&rev_list.stdout)
+        let page_ids: Vec<String> = String::from_utf8_lossy(&rev_list.stdout)
             .lines()
             .map(str::trim)
             .filter(|line| !line.is_empty())
             .map(ToOwned::to_owned)
-            .collect::<Vec<_>>();
-        let (page_ids, page_info) = paginate::paginate(&ids, request.pagination.as_ref());
+            .collect();
 
+        // 3. Batch-read commits via gix (one repo open, no subprocess per commit)
         let mut commits = Vec::with_capacity(page_ids.len());
-        for id in page_ids {
-            commits.push(self.get_commit(GetCommitRequest {
-                repository: request.repository.clone(),
-                revision: Some(crate::pb::ObjectSelector {
-                    selector: Some(object_selector::Selector::Revision(crate::pb::ObjectName {
-                        revision: id,
-                    })),
-                }),
-                include_stats: false,
-                include_raw: false,
-            })?);
+        for id in &page_ids {
+            commits.push(read_commit_from_repo(self, &repo, id)?);
         }
 
+        let end = start_offset + page_ids.len();
+        let has_next = end < total;
+        let page_info = crate::pb::PageInfo {
+            next_page_token: if has_next {
+                end.to_string()
+            } else {
+                String::new()
+            },
+            has_next_page: has_next,
+            total_count: total as u64,
+        };
+
         let diff_stats = diff_stats_for_range(self, &base, &head, None)?;
         Ok(CompareCommitsResponse {
             commits,