Bound network probe timeouts

[vikranthreddimasu]

• Summary: Validate latency and bandwidth probe inputs before socket work.
• Summary: Apply one end-to-end timeout across connect, transfer, receiver acknowledgement, and cleanup.
• Summary: Treat missing bandwidth receiver acknowledgement as probe failure instead of reporting fabricated throughput.
• Security changes: None; authentication, authorization, credentials, TLS, and wire protocols are unchanged.
• Usability changes: Invalid timeout and payload values now raise actionable ValueError messages; failed probes retain documented sentinel results.
• Tests/checks run: python -m pytest tests/test_pool/test_network.py -q (33 passed).
• Tests/checks run: make lint (Ruff passed; mypy passed across 55 source files).
• Tests/checks run: make test (1051 passed, 3 skipped, 2 existing deprecation warnings).
• Tests/checks run: wheel build, git diff --check, and diff-only secret scan passed.
• Tests/checks run: All 11 GitHub Actions jobs passed.
• Commit: 833668a Validate network probe inputs.
• Commit: d58ff24 Bound network probe lifecycles.
• Risks / manual review notes: Low-risk network utility change; timeout semantics are strictly end-to-end and unacknowledged bandwidth probes return 0.0.
• Merge status: Merged into master after all checks passed.