test(spec): the transactions tombstone pin discriminates its own subject

`packages/spec/src/data/driver.test.ts` pinned the `transactions` retired-key
prescription with a regex requiring only that `METHOD PRESENCE` and
`beginTransaction` appear somewhere in the thrown message. #18890 rewrote that
prescription's opening from "gated on METHOD PRESENCE" to "gated on the
DRIVER'S DECLARATION, no longer on METHOD PRESENCE alone" — and the old regex
matches BOTH. Reverting the prescription to the now-false sentence kept the
test green, so the pin could not fail on the one shape it exists to catch. The
title said "points at method presence", which is the old world too.

Anchor on the two things #18890 made load-bearing instead: the negation
(`no longer on METHOD PRESENCE`) and the predicate that replaced presence
(`driverSupportsTransactions`). `beginTransaction` and `Delete the key` stay,
so nothing the old pin covered is dropped.

Deliberately NOT a ban on the phrase `METHOD PRESENCE`: `schemaSync`'s own
"Schema sync is gated on METHOD PRESENCE" sentence in driver.zod.ts is true of
the runtime today and is untouched.

Test-only. No runtime file, no published surface.

Claude-Session: https://claude.ai/code/session_01JbZnqu8bt6YqfJsr9vaFb3
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/spec/src/data/driver.test.ts

@@ -121,9 +121,16 @@ describe('[#4634] the 31 inert capability bits are tombstoned, not stripped', ()
     );
   });
 
-  it('the transactions prescription points at method presence, and says the live bit is not it restored', () => {
+  it('the transactions prescription points at the DECLARATION gate, not method presence alone, and says the live bit is not it restored', () => {
+    // [#18996] Anchored on what #18890 made load-bearing: the NEGATION and the
+    // predicate that replaced method presence. An anchor on `METHOD PRESENCE`
+    // alone matched this prescription's PREVIOUS, now-false opening ('gated on
+    // METHOD PRESENCE — `driver.beginTransaction`') exactly as happily as the
+    // true one, so it could not fail on the one shape it exists to catch. ⛔ Not
+    // a ban on the phrase — `schemaSync`'s own 'gated on METHOD PRESENCE'
+    // sentence is true of the runtime and stays.
     expect(() => DriverCapabilitiesSchema.parse({ transactions: true })).toThrow(
-      /DriverCapabilities\.transactions.*removed.*METHOD PRESENCE.*beginTransaction.*Delete the key/s,
+      /DriverCapabilities\.transactions.*removed.*no longer on METHOD PRESENCE.*driverSupportsTransactions.*beginTransaction.*Delete the key/s,
     );
     // [#18063] The trap this sentence exists to close: a reader who sees a live
     // `transactionsUnsupported` and concludes the retired key came back. It did