[v5] reviewer lane follow-ups deferred from #5480 delivery

[clubanderson]

The #5480 reviewer lane shipped (#5485 implementation, #5515 ledger-sync fix proven by the #5511 Spin model, #5588 adjudication audit events) and is live on a hosted spoke. Deferred items from the delivery, none blocking:

1. G2 — pending-wipe: escalation.Sweep treats CI-pending as not-red and deletes ledger entries, making the distinct-SHA breaker probabilistic. Remains the one pinned expected-fail in src/formal/escalation (witness at 7,706 states). Fix + flip the model expectation.
2. Embedded kick template: reviewer lane uses the hardcoded builder fallback; ship a reviewer-lane.md template per the Phase-4 template plan.
3. Structured hand-off notes: post-reviewer re-escalations go to a human with only labels as context; add a structured note (what the reviewer tried, why it failed).
4. True creation-time ordering: work list orders escalated PRs by PR number as an age proxy; thread real timestamps through ci-failing.json rows.

Refs #5480

[clubanderson]

Verified against current origin/v5 tip d18d03952d6b42345109e01ce6d0a57126711c82.

Status of the four deferred reviewer-lane follow-ups:

• G2 pending-wipe — landed. src/formal/escalation/README.md now says G2 is "FIXED in [v5] reviewer lane follow-ups deferred from #5480 delivery #5617 follow-up", Observation.Pending makes pending a no-op, and src/formal/escalation/run.sh now expects w_pending_wipe to pass.
• Embedded kick template — not landed. src/pkg/scheduler/reviewer_lane.go still identifies buildReviewerMessage as the hardcoded fallback, and there is no reviewer-lane.md template (only reviewer-advisory.md).
• Structured hand-off notes — substantially landed in the reviewer contract. The kick now requires a hive-review audit comment with outcome, evidence, changes/tests, and remaining risk before relabeling/closing, and the one-pass labels (reviewer-passed, reviewer-recommend-close) make that audit record the hand-off context for later humans.
• True creation-time ordering — landed. formatReviewerWorkList carries CreatedAt time.Time from ci_failing.json, sorts by real forge creation time first, falls unknown timestamps back to the old (repo, number) proxy, and renders the opened: timestamp in the work list.

Dispatch plan for the remaining item:

1. Add a default reviewer-lane.md prompt template alongside the other default policies/templates, preserving the current buildReviewerMessage text and variables exactly.
2. Teach scheduler template resolution to render reviewer-role cadence agents from that template before falling back to buildReviewerMessage.
3. Add/extend scheduler tests to prove a role: reviewer agent resolves the template, still enforces ACMM L5+, caps at three oldest PRs, and preserves the no-work/dormant cases.
4. Keep the hardcoded builder temporarily as compatibility fallback, then remove it only after template coverage is green.

Phase-1 PR scope: pure template extraction plus parity tests; no reviewer-lane behavior changes.