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

actor/handler.rs

@@ -166,7 +166,6 @@ impl Actor for GitNodeActor {
                     .ok();
             }
 
-            // ── Election & Role Change ──────────────────────────────────
             GitNodeMessage::ElectPrimary(request, reply) => {
                 let accepted = should_accept_election(&request, state);
                 tracing::info!(

actor/message.rs

@@ -156,7 +156,6 @@ pub enum RepoActorMessage {
     UpdateMetadata(RepositoryHeader),
 }
 
-// ── Election & Role Change Types ──────────────────────────────────────
 
 /// Request for a node to vote in a PRIMARY election.
 #[derive(Debug, Clone)]