feat(api): extend commit and diff services with new functionality

- Add FindCommit, ListCommitsByOid, CommitIsAncestor RPCs to CommitService
- Add CheckObjectsExist, CommitsByMessage, GetCommitStats RPCs to CommitService
- Add LastCommitForPath, CountCommits, CountDivergingCommits RPCs to CommitService
- Add RawDiff, RawPatch, FindChangedPaths RPCs to DiffService
- Add FindMergeBase, WriteRef, SearchFilesByContent RPCs to RepositoryService
- Add SearchFilesByName, ObjectsSize, RepositorySize RPCs to RepositoryService
- Add FindLicense, OptimizeRepository, GetRawChanges RPCs to RepositoryService
- Add FetchRemote, CreateRepositoryFromURL RPCs to RepositoryService
- Implement server handlers for all new RPC methods
- Add new modules for commit counting, finding, and querying features
- Add new modules for diff changed paths and raw operations
- Add new modules for refs and remote operations
- Remove unnecessary comments from various source files
- Update proto definitions with new message types and service methods

diff/get_diff.rs

@@ -50,7 +50,6 @@ impl GitBare {
         let options = request.options.as_ref();
         let want_patch = options.is_some_and(|o| o.include_patch);
 
-        // ── Call 1: --raw -z --numstat -z  (all metadata + line counts) ──
         let (raw_entries, numstat_map) = self.diff_raw_and_numstat(&base, &head, options)?;
 
         let max_files = options.and_then(|o| (o.max_files > 0).then_some(o.max_files as usize));
@@ -59,14 +58,12 @@ impl GitBare {
             &raw_entries[..raw_entries.len().min(max)]
         });
 
-        // ── Call 2 (optional): --patch for all files at once ──
         let patch_map = if want_patch {
             self.diff_patch_batch(&base, &head, options)?
         } else {
             HashMap::new()
         };
 
-        // ── Merge results (zero additional subprocess calls) ──
         let mut files = Vec::with_capacity(entries_to_build.len());
         for entry in entries_to_build {
             let path = if !entry.new_path.is_empty() {
@@ -127,7 +124,6 @@ impl GitBare {
             });
         }
 
-        // ── Call 3: diff --shortstat (already efficient, single call) ──
         let stats = diff_stats_for_range(self, &base, &head, options)?;
         let (files, page_info) = paginate::paginate(&files, request.pagination.as_ref());