Follow-on housekeeping for the Tier-4 plan-readiness audit (PR #124, squash `cb3d1b2`), per the
multi-PR housekeeping discipline that defers the §6 status fold out of the audit-swap PR.

§6 fold (cross-plan-dependencies.md) — mirrors the Tier-3 precedent (030c4ec):

- NS-16 (Tier 4) flips `ready` → `completed`; the Mermaid node splits into a `:::completed` NS-16
  node + a new collapsed `:::ready` NS-17 node, joined by the `NS-16 --> NS-17` audit-chain edge.
- NS-17 (Tier 5) promoted `blocked` → `ready`; NS-18..NS-21 stay `blocked` behind it (strict
  serialization). Status / Priority / Upstream / Summary detail lines + the tier-PR checklist
  (tier-3 de-staled to PR #118, tier-4 checked → PR #124) + the §6 narrative amendment updated.

Plan-007 status `approved` → `review` — applies the mandatory flip PR #124 ratified in REVIEW.md
but never wrote to the file. The Tier-4 audit reopened the Phases 4–7 design (3 new Phases
R1/R2/R3 + 8 new CPs CP-007-7..14 + 12 new invariants I-007-8..19), which triggers the runbook
§Status Flip Rule. The `review` state is the load-bearing downstream-gate signal, and the tracking
state for the contract finalizations still pending (error-contracts `daemon.lifecycle_conflict`
mapping; §3 Plan-007 deps annotation) that land in Plan-007's review→approved cycle / R1 task
T-007r-1-9. Plan-005 + Plan-006 stay `approved` (additive amendments only). The Phases 1–3 partial
(PRs #16/#17/#19) is preserved in-plan as audit evidence and is unaffected.

Validation: prettier --check + lychee (--offline, 0 errors) + docs-corpus pre-commit-runner
(exit 0; mermaid-set-coherence green).

Refs: Plan-005, Plan-006, Plan-007
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Both findings target ripples of this PR's Plan-007 `approved` → `review` flip and
the NS-16 §6 fold; neither was caught by the static mermaid-set-coherence validator
(it checks the narrative's own set-claims against node classes — both authored here).

P2 (cross-plan-dependencies.md §NS-15..21 Summary) — the flip to `review` made the
pre-existing "Plan-017 — the only `review`-status plan" clause contradictory. Reworded
to name both review-status plans and preserve the distinction: Plan-017 is pending-audit
`review` (its Tier-8 audit resolves it); Plan-007 is post-audit-reopen `review` (its own
R1/R2/R3 cycle resolves it, not a pending tier audit). Closes the governance-pointer
gap that could let the reopened Plan-007 promotion cycle be missed.

P2 (cross-plan-dependencies.md §6 Mermaid) — the collapsed `NS-17..NS-21` node was
classed `:::ready`, presenting blocked Tier 6-9 audits as dispatchable. Narrowed NS17
to Tier 5 only (mirroring the NS16 node format) + added an explicit
`NS18[NS-18..NS-21]:::blocked` node + the `NS17 --> NS18` chain edge. The graph now
matches the narrative blocked set `{NS-09, NS-10, NS-18..NS-21}` and the §NS-15..21
Status line, removing the graph-vs-text mismatch.

Validation: prettier --check + lychee (--offline, 0 errors) + docs-corpus pre-commit-runner
(exit 0; mermaid-set-coherence green on the split).

Refs: Plan-007, Plan-017
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

The Plan-007 `approved` -> `review` flip (this PR, d350512) made two README
status assertions stale on lines the diff never touched — invisible to
diff-scoped Codex review and the link/anchor/mermaid validators. Surfaced by a
post-flip ripple sweep (prompted by Codex catching the analogous §6 line 542).

Measured the actual status distribution from docs/plans + docs/specs `Status`
fields rather than inheriting README's own counts (which proved unreliable):

- Plans: 24 `approved` + 1 `completed` (Plan-001) + 2 `review` (Plan-007,
  Plan-017) = 27. README's prior "26 approved" had silently miscounted Plan-001
  as approved (it is `completed`). Corrected line 216 prose + line 259 bullet.
- Specs: 27 `approved` (all). README's "26 approved + Spec-027 in draft" was
  stale since NS-13b's 2026-05-25 Spec-027 `draft` -> `approved` promotion —
  pre-existing, independent of this flip, fixed as an adjacent drive-by found in
  the same sweep (line 260).

Deliberately scoped to the two counts with direct evidence (plans = this flip's
ripple; specs = verified adjacent). The block's other counts (domain models,
architecture docs, runbooks, ADRs) have no staleness signal and were left
untouched.

Refs: Plan-001, Plan-007, Plan-017, Spec-027
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>