fix(canary): accept null events from manage response

Backend serializes `Events []Event` as JSON `null` when the slice is nil
(Go's zero value for slices). Spec §8.4 shows it as an array — stale spec,
verified actual behavior with `curl http://localhost:22784/api/m/<uuid>`
returning `"events": null` on a freshly-created token with no triggers.

Zod schema was `events: z.array(eventResponseSchema)` — failed to parse the
null, threw PARSE_ERROR, manage page rendered "CANNOT REACH ARCHIVE" instead
of the empty dossier.

Fixed: `.nullish().transform(v => v ?? [])` — accepts null/undefined and
normalizes to []. Manage page's `events.length === 0` empty-state check
("No events recorded yet") now reachable; consumers always see an array.

Caught by memory rule feedback_verify_data_shapes.md: trust reality > spec.
I trusted §8.4's example object during Phase 14 schema design instead of
hitting the live endpoint. Same kind of drift as the four Phase-14 spec-vs-code
divergences cleared at the time — this one slipped through because
TokenManagePage was never end-to-end exercised pre-UI.

PROJECTS/beginner/canary-token-generator/frontend/src/api/types/event.ts

@@ -47,7 +47,10 @@ export type ManagePage = z.infer<typeof managePageSchema>
 
 export const manageResponseSchema = z.object({
   token: manageTokenViewSchema,
-  events: z.array(eventResponseSchema),
+  events: z
+    .array(eventResponseSchema)
+    .nullish()
+    .transform((v) => v ?? []),
   events_total: z.number().int().nonnegative(),
   events_silenced_active: z.number().int().nonnegative(),
   page: managePageSchema,