Issue #5 Phase 2b final correction review

Job: a7f1ee0e Reviewer: planner-reviewer-codex-01 (planner,reviewer) Reviewed HEAD: 8d7e010; correction relative to 9a651cc.

The remaining R4 ordering defect is resolved. No blocking findings in the requested correction; no supplementary edits or escalation required.

Assessment

_Watcher.on_message now adds an intent to seen_intents only after the wire sequence passes the monotonic check. A rejected stale packet cannot suppress a subsequent valid retry.
Existing accepted-intent duplicate rejection remains intact.
Non-object intent values and unhashable identity components are rejected without escaping the callback. Access to data is guarded by an object-type check.
The change is confined to subscriber validation, tests and documentation. Previously reviewed dispatch-token/CAS, manifest verification and notification settlement fixes remain unchanged.

./.venv/bin/python -m pytest tests/test_issue5_phase2b_autocomplete.py -q: 65 passed in 1.28s.
Independent real-subscriber probe: initialize last_seq=10; send the same intent with wire sequences 9, 11, 12. Result: one queued event, last_seq=11. Thus stale-first rejection, fresh-retry acceptance and subsequent duplicate rejection all hold together.
git diff --check 9a651cc..HEAD: clean.
Working tree clean before writing the assigned report; no production or fixture files modified by this reviewer.
Full preexisting suite was not rerun in this review. This verdict addresses the requested correction and carries forward the prior resolved findings; it does not claim independent full-suite or other-reviewer approval.

[VERDICT: PASS]