audit(cycle 316): drift disposition, bench seed docs + ratified re-pin, C29 scope paragraph

Cycle-close audit for the self-description cycle. Architect: drift_found
(mild), core holds -- the gate is pure string shape in core imported by
every seam (C28), the engine never evaluates description text (C17/inv
10), determinism pins untouched (C1); the store boundary is gated by
construction with the raw write private; Op::Doc is a closed typed
construct (C25). Regression: aura-bench green (exit 0) after one
cycle-caused infra fix and one ratified re-pin.

Infra fix: the bench campaign seeds (BP_SMA_A/B) predate C29 and were
refused by the store gate (exit 2, infrastructure-first rule) -- both
thread the authored sma_signal meaning line.

Ratify: cli_fixed_cost's run_line_fnv moved because bench_sma_a.json now
carries its doc -- the blueprint's content id shifts exactly as the spec
anticipates for fixtures gaining docs; campaign result fingerprints are
unchanged (descriptions stay out of execution, C29). Baselines re-pinned
via aura-bench pin (throughput baselines re-pinned in the same sweep,
all deltas within tolerance at pin time).

Drift disposition:
- [high] C29 guarantee overclaim vs emit/binding-column vocabularies ->
  contract now carries an explicit Scope paragraph naming the residue,
  tracked as #321 (also covers the [medium] non-roster schema walk gap).
- [low] Delay's meaning line cited the stale C5 for the delay register;
  corrected to C9.

refs #316, refs #321

docs/design/contracts/c29-self-description.md

@@ -33,6 +33,15 @@ and on a doc that normalizes to the entry's own name
    Process/campaign documents take an additive-optional top-level
    `description`, gated only when present (`DocFault::BadDescription`).
 
+**Scope at this record's writing (#321).** The gate walks five
+vocabularies — process/campaign blocks, metrics, tap slots, tap folds, and
+the closed node roster — plus the document `description` and the three
+seams above. Recorded residue, tracked as #321 and not silently claimed:
+`emit_vocabulary()` and `binding_column_vocabulary()` remain bare name
+arrays, and builder schemas outside the closed node roster (e.g. the
+internal tap recording sink) carry compile-required but shape-unwalked
+docs. Closing #321 widens the walk and removes this paragraph.
+
 **Id treatment.** Description fields that serialize participate in the
 content id and are blanked for the identity id, exactly as `Composite.doc`
 (`strip_debug_symbols`); `NodeSchema` is not serialized