Fix file_handles mutex contention in IoClient::close_file method

[coderabbitai]

Problem

The close_file method in src/interpreter/mod.rs currently holds the file_handles mutex while awaiting flush() and sync_all() operations, which serializes all I/O through this mutex and causes contention.

Current Code Location

• File: src/interpreter/mod.rs
• Lines: Around 416-429
• Method: IoClient::close_file

Issue Details

1. The mutex guard is held while awaiting async file operations
2. This prevents concurrent access to file_handles by other tasks
3. flush() on tokio::fs::File is effectively a no-op
4. Should prefer sync_all() for durability and propagate errors properly

Proposed Solution

• Remove the file handle from the HashMap while holding the lock
• Drop the mutex guard immediately after removal
• Perform async sync operations outside the mutex scope
• Use sync_all() with fallback to sync_data() for proper error handling

References

• PR: Enhances project version synchronization processes #165
• Comment: Enhances project version synchronization processes #165 (comment)
• Reported by: @coderabbitai

Priority

This affects I/O performance and concurrency under load, particularly when multiple file operations are happening simultaneously.