The repeat rules are pinned by the shared fixture

daily/weekly/monthly/yearly was written out in the server (REMINDER_RECURRENCES),
the core (recur::RECURRENCES), the web editor's <option>s and Android's picker,
with nothing holding them together. grammar.json now has a recurrences list; the
server, core and web suites each check theirs against it, and the web's options
come from notes/recurrence.ts rather than the template. Android's picker pins the
list by hand with its localised labels, as it does the tint: its JVM tests do not
read the fixture.

DRY pass #2, batch 3 (#5372).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/notes/grammar.test.ts

@@ -8,6 +8,7 @@ import { describe, expect, it } from "vitest";
 import fixture from "../../../core/testdata/grammar.json";
 import { DERIVED_TINT_KEYS, derivedTint, resolveLabelColor, tintHash } from "./colors";
 import { parseInline, parseTaskLine, renderTaskLine } from "./markdown";
+import { RECURRENCES } from "./recurrence";
 
 describe("checklist lines", () => {
   it.each(fixture.task_lines)("$line", ({ line, item }) => {
@@ -52,3 +53,9 @@ describe("derived tag colour", () => {
     expect(resolveLabelColor({ name })).toBe(color);
   });
 });
+
+describe("recurrences", () => {
+  it("offers the stored rules every surface holds", () => {
+    expect(RECURRENCES.map((r) => r.value)).toEqual(fixture.recurrences);
+  });
+});

frontend/src/notes/recurrence.ts

@@ -0,0 +1,9 @@
+// The repeat rules a reminder can carry, as stored, and what the editor calls each.
+// The server (REMINDER_RECURRENCES) and the core (recur::RECURRENCES) hold the same
+// list, and all three run the `recurrences` case in core/testdata/grammar.json.
+export const RECURRENCES: ReadonlyArray<{ value: string; label: string }> = [
+  { value: "daily", label: "Daily" },
+  { value: "weekly", label: "Weekly" },
+  { value: "monthly", label: "Monthly" },
+  { value: "yearly", label: "Yearly" },
+];