fix(forms): don't ask for an end date the form is hiding

With "Comes back after a wait" and "I don't know when it ends" both
chosen, the end field is hidden, yet the still-needed line asked for "an
end date". It now names the way out: an end date, or another repeat.

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

src/client/components/CustomForms.tsx

@@ -455,7 +455,11 @@ export function eventStillNeeded(s: {
   const needs: string[] = [];
   if (s.title.trim() === "") needs.push("a name");
   if (s.startDate === "") needs.push("a start date");
-  if ((s.datedWindow && s.endKnown && s.endDate === "") || s.delayNeedsEnd) {
+  if (s.delayNeedsEnd && !s.endKnown) {
+    // The end field is hidden behind "I don't know when it ends", so a bare
+    // "an end date" would ask for something not on screen.
+    needs.push("an end date (a wait counts from it) or another repeat");
+  } else if ((s.datedWindow && s.endKnown && s.endDate === "") || s.delayNeedsEnd) {
     needs.push("an end date");
   }
   if (s.needsCycle) needs.push("a cycle length");

test/form-examples.test.tsx

@@ -259,7 +259,7 @@ describe("what an event still needs", () => {
     expect(eventStillNeeded({ ...base, endDate: "", endKnown: false })).toEqual([]);
     expect(eventStillNeeded({ ...base, endDate: "", datedWindow: false })).toEqual([]);
     expect(eventStillNeeded({ ...base, endKnown: false, delayNeedsEnd: true })).toEqual([
-      "an end date",
+      "an end date (a wait counts from it) or another repeat",
     ]);
     expect(eventStillNeeded({ ...base, needsCycle: true })).toEqual(["a cycle length"]);
   });
@@ -338,3 +338,22 @@ describe("review fixes: Save never sits disabled without a reason", () => {
     expect(filled.needs).toEqual([]);
   });
 });
+
+describe("follow-up: a wait with the end set to unknown", () => {
+  test("names the way out instead of asking for a field it hides", () => {
+    const v: EventFormValues = {
+      ...blankEvent,
+      title: "x",
+      cadence: "custom",
+      repeatMode: "delay",
+      endKnown: false,
+      startDate: "2026-10-01",
+      endDate: "",
+    };
+    expect(eventFormState(v, null).needs).toEqual([
+      "an end date (a wait counts from it) or another repeat",
+    ]);
+    // With the end field on screen, the plain words are enough.
+    expect(eventFormState({ ...v, endKnown: true }, null).needs).toEqual(["an end date"]);
+  });
+});