refactor(cache): redesign cache system with structured keys and improved performance

- Add repo_path parameter to cached_response and cached_vec_response functions
- Implement structured cache key format with namespace, repo_path, and request proto
- Replace global cache with Moka in-memory cache using weight-based eviction
- Set 256MB memory cap with 10-minute TTL and 2-minute TTI policy
- Add metrics collection for cache operations and evictions
- Implement efficient repo-scoped invalidation using key structure
- Add detailed documentation comments explaining cache architecture
- Remove outdated dependencies and update dependency versions
- Add error handling for encoding failures in cache operations
- Optimize Vec responses with length-delimited encoding and pre-allocation

branch/set_branch_upstream.rs

@@ -6,6 +6,8 @@ impl GitBare {
     pub fn set_branch_upstream(&self, request: SetBranchUpstreamRequest) -> GitResult<Branch> {
         crate::sanitize::validate_ref_name(&request.name)?;
         if let Some(upstream) = request.upstream {
+            crate::sanitize::validate_ref_name(&upstream.remote_name)?;
+            crate::sanitize::validate_ref_name(&upstream.remote_branch_name)?;
             let tracking = format!("{}/{}", upstream.remote_name, upstream.remote_branch_name);
             let result = duct::cmd(
                 "git",