⚡ Optimize JobControl to use async fs operations

[google-labs-jules]

💡 What:
Replaced fs.existsSync and fs.statSync with await fs.promises.access and await fs.promises.stat in src/api/controls/JobControl.ts.

🎯 Why:
The synchronous file system operations block the Node.js event loop, which can degrade performance in a high-concurrency environment or when handling large files. Switching to asynchronous operations allows other tasks to be processed while waiting for I/O.

📊 Measured Improvement:
Micro-benchmarking a single call in a mocked environment showed a slight increase in execution time due to Promise overhead (from ~0.06ms to ~0.5ms per call), which is expected and negligible for file uploads. The primary benefit is the non-blocking nature of the new implementation, allowing for better scalability and responsiveness of the application.

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PR created automatically by Jules for task 8736435367009031723 started by @GhostTypes

[google-labs-jules]

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