fix: bootstrap and trust Codex OMI hooks

[CryptoJones]

Summary

• install Codex SessionStart OMI priming during setup
• add managed global AGENTS.md OMI bootstrap pointer
• persist per-machine Codex hook trust hashes for omind-owned hooks
• bump release version to 3.7.2

Tests

• .venv/bin/pytest tests/test_agents.py tests/test_hooks.py tests/test_provision.py tests/test_cli_integration.py tests/test_cli.py -q
• .venv/bin/pytest tests/test_lint.py -q
• .venv/bin/ruff check .
• git diff --check

Note: full .venv/bin/pytest -q currently fails in tests/test_embed.py::test_real_similarity_orders_paraphrase_above_unrelated because embed.similarity() returns None in this local optional embed environment.