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/delete_branch.rs

@@ -0,0 +1,23 @@
+use std::process::Command;
+
+use crate::bare::GitBare;
+use crate::error::{GitError, GitResult};
+use crate::pb::DeleteBranchRequest;
+
+impl GitBare {
+    pub fn delete_branch(&self, request: DeleteBranchRequest) -> GitResult<()> {
+        let flag = if request.force { "-D" } else { "-d" };
+        let output = Command::new("git")
+            .arg("--git-dir")
+            .arg(&self.bare_dir)
+            .args(["branch", flag, &request.name])
+            .output()?;
+        if !output.status.success() {
+            return Err(GitError::CommandFailed {
+                status_code: output.status.code(),
+                stderr: String::from_utf8_lossy(&output.stderr).into_owned(),
+            });
+        }
+        Ok(())
+    }
+}