fix(runtime): read the record number as a string in the autonumber parity probe (#15267)

`SqlDriver.create()` declares the contract's `Record<string, unknown>` now, so
the cross-side parity probe's `rec_no` read is `unknown` where it was reached
through an `any`. It converts to the string the probe compares.

Caught by this package's `check:test-typecheck` gate, not by `tsc --noEmit` —
the file is in the checked test zone and the ledger does not cover it.

Claude-Session: https://claude.ai/code/session_01XTBcV7zZHmokdyQgXjbyEU
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/runtime/src/autonumber-seed-cross-side-parity.integration.test.ts

@@ -144,7 +144,10 @@ async function sqlDriverIssues(format: string | undefined, stored: string[]): Pr
 
   const created = await driver.create('rec', { title: 'next' });
   await driver.disconnect();
-  return created.rec_no;
+  // [#15267] `SqlDriver.create()` declares the contract's
+  // `Record<string, unknown>` now, so the record number is read as the string
+  // this parity probe compares — it was reached through an `any` before.
+  return String(created.rec_no);
 }
 
 interface Fixture {