fix(agent): bound context compression summary stalls

[LeonSGP43]

Summary

• run compression summary generation behind a worker-thread hard timeout keyed to auxiliary.compression.timeout
• fall back to the existing deterministic summary path instead of blocking the dashboard/gateway loop indefinitely
• add regression coverage for the hard-timeout wrapper contract

Fixes #49768

Testing

• pytest tests/agent/test_context_compressor.py -q
• pytest tests/run_agent/test_413_compression.py -q
• pytest tests/run_agent/test_compression_feasibility.py -q
• ruff check agent/context_compressor.py tests/agent/test_context_compressor.py
• git diff --check

[kshitijk4poor]

Superseded by #56295, which carries your commit verbatim (authorship preserved) rebased onto current main (this was ~592 commits behind; two cosmetic conflicts resolved), plus a rebase follow-up. Fixing the rebase surfaced a real production gap: the hard TimeoutError was being classified as a network close (_is_connection_error matches any 'Timeout'-named exception), so compress() ABORTED instead of falling back — the opposite of your intent. Gated it (_is_streaming_closed = ... and not _is_timeout), mutation-verified against your own test. Ran hermes-agent-dev + hermes-pr-review Phase 2c (0 Critical). Full credit to you for the fix and the test that caught the gap. Closing in favor of #56295 — feel free to push back.