[feat] - Concurrent processing of binary diffs during git scans

[ahrav]

Description:

Refactor Git repo scanning to use workers for asynchronous processing of binary diffs.

• Introduce a buffered binaryDiffChan to distribute work
• Start N goroutine workers to handle binary diffs
• Scan commits and staged changes concurrently using WaitGroup
• Close diff channel when producers finish
• Synchronize consumer completion before exiting
• Propagate first error to cancel context
• Return early if error occurs processing diffs (this preserves existing functionality)

High level design:

This refactors the scanning logic to utilize concurrency and avoid blocking on large binaries. Multiple goroutines can now process diffs asynchronously through the buffered channel.

The context cancellation allows all workers to exit cleanly if an error happens. And synchronization points ensure proper shutdown.

This should help increase overall scanning throughput, while maintaining existing control flow around error handling.

Checklist:

• Tests passing (make test-community)?
• Lint passing (make lint this requires golangci-lint)?