hermes - 💡(How to fix) Fix [Feature]: Add goal lifecycle plugin hooks (on_goal_set/pause/resume/complete)

Summary

The /goal system has a complete state machine (set → evaluate → pause → resume → complete), but this lifecycle is completely invisible to the plugin system. While Hermes exposes hook points for sessions (on_session_start/end), LLM calls (pre/post_llm_call), and API requests (pre/post_api_request), there is no way for a plugin to observe or react to goal lifecycle events.

This makes it impossible for plugins to:

• Monitor goal progress or completion status
• Log goal auto-pauses (e.g. due to API errors, as fixed by #27585)
• Send notifications when a goal pauses or completes
• Build custom integrations based on goal state changes

Proposed Hooks

Benefits

• Observability: Plugins can track goal progress in external systems (Langfuse, PostHog, etc.)
• Notifications: Goal auto-pauses can trigger user notifications beyond terminal output
• Extensibility: Third-party plugins can implement custom goal judges, completion alerts, or analytics

Implementation Notes

• All new hooks should be fire-and-forget (no return value modification), consistent with the existing hook contract
• Hook invocation points in hermes_cli/goals.py: set(), pause(), resume(), judge_goal()
• No breaking changes — existing behavior is preserved
• The internal goal continuation hook in cli.py/gateway/run.py is an internal implementation detail; this proposal adds the plugin-visible hook layer

Related

• #27585 — Recent fix for goal API error auto-pause (would benefit from on_goal_pause hook for notification)
• agent/conversation_loop.py — Contains all existing _invoke_hook() calls for reference pattern