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/raw.rs

@@ -0,0 +1,89 @@
+use crate::bare::GitBare;
+use crate::error::GitResult;
+use crate::pb::*;
+
+impl GitBare {
+    /// Stream raw diff output.
+    pub fn raw_diff(&self, request: RawDiffRequest) -> GitResult<Vec<RawDiffResponse>> {
+        let base = &request.base;
+        let head = &request.head;
+        crate::sanitize::validate_revision(base)?;
+        crate::sanitize::validate_revision(head)?;
+
+        let mut args = vec![
+            "--git-dir".to_string(),
+            self.bare_dir.to_string_lossy().into_owned(),
+            "diff".to_string(),
+        ];
+
+        // Apply options if present
+        if let Some(ref opts) = request.options {
+            if opts.recursive { args.push("--recursive".to_string()); }
+            if opts.include_binary {
+                args.push("--binary".to_string());
+            } else {
+                args.push("--no-binary".to_string());
+            }
+            for ps in &opts.pathspec {
+                args.push("--".to_string());
+                args.push(ps.clone());
+            }
+        }
+
+        args.push(base.clone());
+        args.push(head.clone());
+
+        let output = std::process::Command::new("git")
+            .args(&args)
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .output()
+            .map_err(|e| crate::error::GitError::CommandFailed {
+                status_code: None,
+                stderr: e.to_string(),
+            })?;
+
+        // Chunk the output for streaming
+        const CHUNK_SIZE: usize = 32768;
+        let data = output.stdout;
+        let chunks: Vec<RawDiffResponse> = data
+            .chunks(CHUNK_SIZE)
+            .map(|c| RawDiffResponse { data: c.to_vec() })
+            .collect();
+
+        Ok(chunks)
+    }
+
+    /// Stream raw patch (format-patch) output.
+    pub fn raw_patch(&self, request: RawPatchRequest) -> GitResult<Vec<RawPatchResponse>> {
+        crate::sanitize::validate_revision(&request.base)?;
+        crate::sanitize::validate_revision(&request.head)?;
+
+        let range = format!("{}..{}", request.base, request.head);
+
+        let output = std::process::Command::new("git")
+            .args([
+                "--git-dir",
+                &self.bare_dir.to_string_lossy(),
+                "format-patch",
+                "--stdout",
+                &range,
+            ])
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .output()
+            .map_err(|e| crate::error::GitError::CommandFailed {
+                status_code: None,
+                stderr: e.to_string(),
+            })?;
+
+        const CHUNK_SIZE: usize = 32768;
+        let data = output.stdout;
+        let chunks: Vec<RawPatchResponse> = data
+            .chunks(CHUNK_SIZE)
+            .map(|c| RawPatchResponse { data: c.to_vec() })
+            .collect();
+
+        Ok(chunks)
+    }
+}