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

branch/create_branch.rs

@@ -0,0 +1,36 @@
+use std::process::Command;
+
+use crate::bare::GitBare;
+use crate::error::{GitError, GitResult};
+use crate::pb::{Branch, CreateBranchRequest, GetBranchRequest, object_selector};
+
+impl GitBare {
+    pub fn create_branch(&self, request: CreateBranchRequest) -> GitResult<Branch> {
+        let revision = match request.start_point.and_then(|s| s.selector) {
+            Some(object_selector::Selector::Oid(oid)) => oid.hex,
+            Some(object_selector::Selector::Revision(name)) => name.revision,
+            None => "HEAD".into(),
+        };
+        let mut args = vec!["branch".to_string()];
+        if request.force {
+            args.push("-f".into());
+        }
+        args.push(request.name.clone());
+        args.push(revision);
+        let output = Command::new("git")
+            .arg("--git-dir")
+            .arg(&self.bare_dir)
+            .args(&args)
+            .output()?;
+        if !output.status.success() {
+            return Err(GitError::CommandFailed {
+                status_code: output.status.code(),
+                stderr: String::from_utf8_lossy(&output.stderr).into_owned(),
+            });
+        }
+        self.get_branch(GetBranchRequest {
+            repository: request.repository,
+            name: request.name,
+        })
+    }
+}