[Adapter] Support Hermes CLI

[teseo]

Kind

implement

Goal

Integrate human.md with Hermes using plugin or shell hooks for pre-tool, session, and context events.

Non-goals

• Adding a Hermes-specific policy engine.
• Treating fail-open hook errors as hard enforcement.
• Supporting unrelated Hermes gateway deployment behavior.

Invariants

• pre_tool_call deny is explicit and tested.
• Hook errors and timeouts have a documented fail-open or wrapper fail-closed policy.
• JSON stdin/stdout remains compatible with Hermes hook execution.
• Session state is isolated and cleaned up.

Behavioral contract / States

Translate Hermes pre_tool_call, post_tool_call, pre_llm_call, on_session_start, and on_session_end into canonical events. Return the expected hook response and preserve a diagnostic trail for hook failures.

Scope surface

Hermes plugin/shell hook adapter, configuration examples, timeout handling, and tests.

Acceptance

• Verify a blocked pre_tool call does not execute.
• Verify session start/end and context injection fixtures.
• Test hook timeout and malformed JSON behavior.
• Run: python3 -m pytest tests/test_guard.py -v and the Hermes adapter smoke test.

Split triggers

• Plugin and shell hooks have incompatible semantics that cannot share one adapter.
• Gateway-only behavior needs a separate delivery contract.

Dependencies / Parent

Blocked by: #1, #2, #3
Parent Epic: #15