fix(agent): migrate goal state across compression session rotation

[sharziki]

Summary

• Goal state is stored in state_meta under goal:<session_id>; when context compression rotates the session_id, GoalManager for the new id finds no goal — the user's /goal silently disappears
• Copy the active goal to the continuation session's key during compression, following the same pattern used for session titles, system prompts, context engine hooks, and memory manager hooks
• Defensive: wrapped in try/except, logs on failure, no-op if no active goal

Test plan

• New test test_goal_migrates_across_session_rotation in tests/hermes_cli/test_goals.py
• All 51 goal tests pass

Closes #33618

🤖 Generated with Claude Code

[alt-glitch]

Competing with #33890, #33620, #29955, #18749, and #18427 — all fix #33618 (goal lost after compression session rotation). Prior fix #23530 was merged then reverted in #23813. Maintainer should pick one.

[teknium1]

Thanks for this — the diagnosis and fix are correct for the rotation path.

Context on why we're closing it: as of #52658 (#38763), compression.in_place now defaults to True. Compaction keeps ONE durable session id for the conversation's whole life — it no longer ends the session and forks a continuation id. Because the id no longer rotates, the active /goal stays attached to the same session automatically — there is no rotation boundary to migrate the goal across.

Rotation now only runs as an explicit opt-out (compression.in_place: false), and the direction is to treat that path as legacy. So this fix hardens a code path that no longer executes by default and that we're not investing further in. Closing as superseded by the in-place default — not a reflection on the code, which was a correct fix for the behavior at the time. Credit preserved in the issue/PR history. Appreciate the contribution.