CC-1/M0: optional recipient meta on StateNode

[soltrinox]

Summary

Implements CC-1 / M0 for comPASS Track B on engine 0.2.0.

• Add optional recipient_id, recipient_version, route_decision_id to PersistentAgentHandle.step so they persist on StateNode.meta
• Round-trip through StateStore save/load/lineage (already JSON-backed meta_json; documented RECIPIENT_META_KEYS)
• Extend engine/schema/state-node.v1.json meta properties
• Tests prove present fields survive lineage reload; absent fields keep 0.2.0 meta shape

Out of scope: CC-2..CC-10 (not included).

Acceptance criteria

1. Unit: write a node with all three fields; reload via StateStore; assert equality
2. Lineage: parent/child chain keeps per-turn recipient
3. Absent fields ⇒ prior behavior (tool_status + tokenizer_id only from step)
4. No /Users/rosario paths in engine/ source
5. Relevant pytest: tests/test_store.py + tests/test_handle.py — 5 passed

Files changed

• engine/src/chat_compressor/handle.py
• engine/src/chat_compressor/store.py
• engine/schema/state-node.v1.json
• engine/tests/test_handle.py
• engine/tests/test_store.py

Test plan

• cd engine && python -m pytest tests/test_store.py tests/test_handle.py -v (5 passed)
• rg -n '/Users/rosario' engine/ → no hits
• Reviewers: confirm no CC-2+ leakage

Contract: comPASS docs/schema/statenode-meta.v1.md

[soltrinox]

M1 / CC-2..CC-5 landed on this branch

Hop safety prerequisites for model switching (Track B milestone M1). Continues M0/CC-1 on compass/m0-cc1-recipient-meta.

Changes

• CC-2: inject_history.json partitions by recipient_id (recipients map); absent id keeps session-scoped turns (0.2.0).
• CC-3: pack_forward(..., recipient_changed=True) clears suppression like supersede.
• CC-4: allow_skip gated on recipient continuity; first/hop turn never skips.
• CC-5: adaptive_budget uses per-recipient lineage turn count, not session t alone.

Proof

• pytest touched suite: store/pack/handle + tests/test_m1_hop_safety.py — all passed (logs under local test-results/m1-hop-safety/, gitignored).
• Sanitize: rg \"/Users/rosario\" engine/ clean.
• M1 exit: hop at turn 20 → non-skip, full budget, unsuppressed payload; no-hop tagged session matches absent-recipient token accounting.

Commits

• 9db1564 feat(engine): CC-2..CC-5 per-recipient hop safety (M1)
• 28244cd test(engine): polish M1 hop-safety assertions and comments

Still out of scope on this PR

CC-6..CC-10, HOOK_CONTRACT advisory (CC-9), bundle export (CC-8).