feat(core): implement Git repository operations with gRPC services

- Add advertise_refs functionality for Git protocol communication
- Implement archive service with TAR/ZIP format support and streaming
- Create blame service for Git file annotation with line tracking
- Add branch management including create, delete, rename and compare operations
- Implement merge checking with conflict detection and fast-forward handling
- Add cherry-pick functionality for applying commits between branches
- Integrate gix library for Git repository operations and object handling
- Add comprehensive test suite covering all Git operations
- Implement proper error handling and repository validation
- Add pagination support for large result sets
- Create protobuf definitions for all Git operations and data structures
- Add build system for gRPC code generation and dependency management

blob/get_raw_blob.rs

@@ -0,0 +1,16 @@
+use crate::bare::GitBare;
+use crate::error::GitResult;
+use crate::pb::{GetBlobRequest, GetRawBlobRequest, GetRawBlobResponse};
+
+impl GitBare {
+    pub fn get_raw_blob(&self, request: GetRawBlobRequest) -> GitResult<Vec<GetRawBlobResponse>> {
+        let blob = self.get_blob(GetBlobRequest {
+            repository: request.repository,
+            revision: request.revision,
+            path: request.path,
+            oid: request.oid,
+            max_bytes: 0,
+        })?;
+        Ok(vec![GetRawBlobResponse { data: blob.data }])
+    }
+}