docs(tests): two docblocks stop citing files the retirement deleted

Both are comment-only; no assertion, no harness and no gate input moves.

`plugin-audit/src/read-audit-view-instant-preservation.integration.test.ts`
named `migrate-sys-notification-to-event.test.ts` and
`packages/runtime/src/notification-migration-audit-preservation.integration.test.ts`
as files a reader could go open. Both are absent from the tree (measured, with a
sibling that IS present as the positive control). They are now marked retired;
the first is kept because the SHAPE it demonstrated is the paragraph's point.

`metadata/src/migrations/raw-exec-operator-detail-16657.test.ts` said "at the
three `err?.message ?? String(err)` sites". Two remain. Measured rather than
carried: the directory holds two `catch (err: any)` sites recording through
`operatorFacingErrorText` and one `catch (error)` site, matching the docblock's
own two-expression split; and the pre-merge tree of `d64bcb6377` shows the third
in the deleted `migrate-sys-notification-to-event.ts`, which returned
`{ outcome: 'failed', reason: err?.message ?? String(err) }`.

Claude-Session: https://claude.ai/code/session_01DvvamiacK328idtBYJBxV3
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/metadata/src/migrations/raw-exec-operator-detail-16657.test.ts

@@ -23,12 +23,16 @@
  * ⚠️ That channel is a RULE, not byte-identity with what these `catch` blocks
  * used to compute, and the negative pins below do not claim otherwise: each
  * throws a NON-EMPTY `new Error(…)`, the shape for which the rule and the old
- * expression agree. They differ elsewhere — at the three `err?.message ??
+ * expression agree. They differ elsewhere — at the two `err?.message ??
  * String(err)` sites `new Error('')` recorded `''` and now records `'Error'`,
  * and `{message:42}` recorded the number where it now records
  * `'[object Object]'`; at the `error instanceof Error ? … : String(error)` site
  * `{message:'x'}` recorded `'[object Object]'` and now records `'x'`.
  *
+ * ⚠️ Two, not the three this said when it was written. The third was
+ * `migrateSysNotificationToEvent`, and it went with that runner when the
+ * adr-0030-notification-event migration was retired.
+ *
  * ⚠️ The composed sentence is the producer's, copied; `driver-sql`'s
  * `sql-driver-16657-operator-facing-cause-text.test.ts` pins the copy against a
  * real `SqlDriver.execute()` refusal.

packages/plugins/plugin-audit/src/read-audit-view-instant-preservation.integration.test.ts

@@ -15,18 +15,21 @@
  * the driver stores, on BOTH sides of any change to the write's context. The
  * case is green today, was green before #15964 flattened the ordinary insert
  * branch, and stays green after this card's fix. An instrument that cannot fail
- * is indistinguishable from a pass — the same shape that let
+ * is indistinguishable from a pass — the same shape that let the since-retired
  * `migrate-sys-notification-to-event.test.ts` read `23 passed` for #16312 while
- * the rows it described were being restamped.
+ * the rows it described were being restamped. That file went with the
+ * adr-0030-notification-event migration it covered; it is named here for the
+ * SHAPE it demonstrated, not as a file to go read.
  *
  * ⇒ this file is the instrument that CAN fail. It boots a real
  * {@link ObjectKernel} with the real {@link ObjectQLPlugin} (so the shipped
  * audit stamp hooks are registered) over a real {@link SqliteWasmDriver}, and
  * reads the persisted row back through the driver's own SQL surface.
  *
  * ⚠️ Unlike #16312's equivalent (`packages/runtime/src/notification-migration-
- * audit-preservation.integration.test.ts`), this one lives beside the code it
- * tests. That file had to leave `packages/metadata` because
+ * audit-preservation.integration.test.ts`, retired together with the migration
+ * it covered and no longer in the tree), this one lives beside the code it
+ * tests. That file had had to leave `packages/metadata` because
  * `@objectstack/objectql` depends on it and the test-only import would have
  * closed a cycle. Here the edge already runs the other way —
  * `@objectstack/plugin-audit` depends on `@objectstack/objectql` — and