Replace the inlined price sheet with a pointer to the live file

The copy in MetricsAndScenarios 1a went stale within hours of T11: it
still showed the sonnet intro rate as a comment after the real sheet
moved dated rates into data. A spec that duplicates a data file will
always drift from it; the copy is now a pointer that says so.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

specs/MetricsAndScenarios.md

@@ -94,27 +94,11 @@ benchmarks/baselines/model-prices.toml   # the price sheet, updated when prices
 ```
 
 ```toml
-# USD per million tokens; source: Anthropic pricing, recorded 2026-07-31
-[claude-fable-5]
-input = 10.00
-output = 50.00
-
-[claude-opus-5]
-input = 5.00
-output = 25.00
-
-[claude-sonnet-5]
-input = 3.00    # intro 2.00 through 2026-08-31
-output = 15.00  # intro 10.00 through 2026-08-31
-
-[claude-haiku-4-5]
-input = 1.00
-output = 5.00
-
-[cache]                 # multipliers on the input price
-read = 0.1
-write_5m = 1.25
-write_1h = 2.0
+# The live sheet is benchmarks/baselines/model-prices.toml — read it,
+# do not copy it. An inlined copy here went stale within hours: it still
+# showed the sonnet intro rate as a `#` comment after CB-WP-0003 T11 made
+# dated rates into data (promo_input / promo_output / promo_until), and
+# added `recorded` + `max_age_days` for the staleness check (CA-16/CA-17).
 ```
 
 Rules:
@@ -135,7 +119,8 @@ Rules:
   failed pass scores nothing.
 - Prices are `adopted:anthropic-pricing` with a recorded date; a stale sheet
   (> 90 days or known price change) invalidates new `better` verdicts on
-  M-D2-CST until refreshed.
+  M-D2-CST until refreshed. **Now enforced** — CA-17 aborts the run rather
+  than leaving this as prose every verdict silently inherited.
 
 Determinism is not a metric but an **invariant**: N replays of the same
 seed and command log must produce bit-identical state hashes. Invariant