Fix plugin config sporadic and fix proxy test

[rasapala]

🛠 Summary

Proxy Issue #4172
Detect if proxy is set - norma path
Proxy not set - test timeout on HF_ENDPOINT

Fix sporadic Windows segfault in loadModel with numeric plugin config
Root cause fix: openvinotoolkit/openvino#35714

OVMS passes plugin_config_t (std::map<std::string, ov::Any>) to
compile_model, but ov::Any values for numeric properties like NUM_STREAMS
can carry either int64_t or std::string depending on the code path.
OpenVINO's CPU plugin unconditionally calls val.asstd::string() on all
properties, triggering an unsafe iostream conversion when the value is
numeric — causing sporadic memory corruption and segfault on Windows.

Add a typed normalization table in prepareDefaultPluginConfig that converts
known numeric/bool properties (NUM_STREAMS, INFERENCE_NUM_THREADS,
AUTO_BATCH_TIMEOUT, ENABLE_CPU_PINNING) from string to their native type
before compile_model is called. String-typed properties like PERFORMANCE_HINT
are untouched. Normalization also recurses into nested DEVICE_PROPERTIES maps.

🧪 Checklist

• Unit tests added.
• The documentation updated.
• Change follows security best practices.
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[Copilot]

Pull request overview

This PR updates the Hugging Face pull/clone timeout test to behave deterministically across environments by controlling proxy usage and the remote endpoint used during the clone attempt.

Changes:

• Forces a direct (no-proxy) connection in TestInvalidProxyTimeout so libgit2’s connect-timeout setting is applied.
• Overrides HF_ENDPOINT to an unroutable TEST-NET-1 IP to avoid relying on real huggingface.co connectivity for the test outcome.