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_blob.rs

@@ -0,0 +1,70 @@
+use gix::object::tree::EntryKind;
+
+use crate::bare::GitBare;
+use crate::error::{GitError, GitResult};
+use crate::pb::{Blob, GetBlobRequest, object_selector};
+
+impl GitBare {
+    pub fn get_blob(&self, request: GetBlobRequest) -> GitResult<Blob> {
+        let repo = self.gix_repo()?;
+        let (blob, mode, path) = if let Some(oid) = request.oid.as_ref() {
+            let id = gix::hash::ObjectId::from_hex(oid.hex.as_bytes())
+                .map_err(|e| GitError::InvalidOid(e.to_string()))?;
+            (
+                repo.find_object(id)?
+                    .try_into_blob()
+                    .map_err(|e| GitError::Gix(e.to_string()))?,
+                0,
+                request.path,
+            )
+        } else {
+            let revision = match request.revision.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 tree = repo
+                .rev_parse_single(format!("{}^{{tree}}", revision).as_str())?
+                .object()?
+                .try_into_tree()
+                .map_err(|e| GitError::Gix(e.to_string()))?;
+            let entry = tree
+                .lookup_entry_by_path(&request.path)?
+                .ok_or_else(|| GitError::NotFound(request.path.clone()))?;
+            let mode = u32::from_str_radix(&format!("{:o}", entry.mode()), 8).unwrap_or(0);
+            if !matches!(
+                entry.mode().kind(),
+                EntryKind::Blob | EntryKind::BlobExecutable | EntryKind::Link
+            ) {
+                return Err(GitError::InvalidArgument(
+                    "path does not point to a blob".into(),
+                ));
+            }
+            (
+                entry
+                    .object()?
+                    .try_into_blob()
+                    .map_err(|e| GitError::Gix(e.to_string()))?,
+                mode,
+                request.path,
+            )
+        };
+        let original_size = blob.data.len() as i64;
+        let mut data = blob.data.clone();
+        let truncated = request.max_bytes > 0 && data.len() > request.max_bytes as usize;
+        if truncated {
+            data.truncate(request.max_bytes as usize);
+        }
+        let hex = blob.id.to_string();
+        Ok(Blob {
+            oid: Some(self.oid_to_pb(hex)),
+            path,
+            mode,
+            size: original_size,
+            binary: blob.data.contains(&0),
+            encoding: String::new(),
+            truncated,
+            data,
+        })
+    }
+}

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 }])
+    }
+}

blob/mod.rs

@@ -0,0 +1,2 @@
+pub mod get_blob;
+pub mod get_raw_blob;