Fix hardware detection, optimize dashboard, update README

[Cylae]

This PR addresses the user's request to "Check. Fix. Optimize. Update the README."

Changes:

1. Fix: Added sys.refresh_disks() in server_manager/src/core/hardware.rs because refresh_disks_list() only updates the partition list, not usage stats.
2. Optimize: Refactored server_manager/src/interface/web.rs to offload blocking sysinfo calls (initialization and dashboard refresh) to tokio::task::spawn_blocking. This prevents the async executor from stalling during heavy I/O or computation.
3. Config: Updated server_manager/Cargo.toml to include features = ["async_tokio"] for criterion to support async benchmarking.
4. Docs: Updated README.md to document the requirement of the async_tokio feature for running benchmarks.

Verification:

• cargo check passed.
• cargo test passed.
• Logic verified via code review.

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PR created automatically by Jules for task 11603564308756225289 started by @Cylae

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