Second extraction pass: the strings the codemod could not see

`i18n:coverage` reported 100% while a hundred-odd strings rendered
English in every language. It was not wrong about what it measured: it
reads JSX text, and none of these were JSX text. They were toast
arguments, `confirmDialog({ title, confirmLabel })` props, `title=` and
`aria-label=` attributes, and template literals — every one built from an
expression the codemod cannot read.

176 source strings and 15 plural sets now go through t() and plural(),
translated into all nine languages. Where English put a word in a slot,
the sentence is spelled out per branch instead: `Filter ${verb}` became
"Filter saved" and "Filter created", because which word agrees with what,
and where it sits, is not a property English gets to decide for everyone.
Counts that were `${n} message${n === 1 ? "" : "s"}` are plural() calls,
so Russian and Ukrainian get three forms and Japanese and Chinese get the
one they actually have.

Two of the catalogue's own conventions were worth learning the hard way.
Plural entries are keyed on the English *other* form, not `one` — `one`
is a form English happens to have and Japanese does not. And a constant
table holding English that is translated at the render site is fine: the
literal is a key, not a leak.

Which is what the new check encodes. `scripts/i18n-literals.mjs` accepts
a string that is wrapped where it is written or is a catalogue key
somewhere, and refuses one that is neither — a string no catalogue can
translate, however many languages ship. It found twenty more than my own
sweep had, including the stale-folder toast seen in production. It runs
as part of `npm run i18n:check`.

Also fixed: the catalogue is now awaited before the first paint. The
tree is rebuilt when a catalogue lands, so components recover on their
own, but a string computed in an effect does not — a toast fired in that
gap is emitted in English and stays English. The wait costs nothing
visible, since the session bootstrap already shows a spinner and English
resolves immediately.

And the Japanese agenda title loses a space Japanese does not use:
"{date} からの予定" was written with the English habit of spacing around
a placeholder.

web/src/views/calendar/scope.ts

@@ -1,6 +1,7 @@
 import { choiceDialog, confirmDialog } from "@/ui/dialog";
 import { isOccurrence, isRecurring, isThisAndFutureRefusal, type EventScope } from "@/store/calendar";
 import type { CalendarEvent } from "@/jmap/types";
+import { plural, t } from "@/lib/i18n";
 
 /**
  * Ask which of a series a change is meant for, when there is a choice.
@@ -32,22 +33,22 @@ export async function askScope(
 /** The scope question for deleting. */
 export const askDeleteScope = (event: CalendarEvent): Promise<EventScope | null> =>
   askScope(event, {
-    title: "Delete this event?",
-    occurrenceLabel: "This occurrence",
-    occurrenceHint: "Removes this date and leaves the rest of the series.",
-    seriesLabel: "All occurrences",
-    seriesHint: "Deletes the whole series. This cannot be undone.",
+    title: t("Delete this event?"),
+    occurrenceLabel: t("This occurrence"),
+    occurrenceHint: t("Removes this date and leaves the rest of the series."),
+    seriesLabel: t("All occurrences"),
+    seriesHint: t("Deletes the whole series. This cannot be undone."),
     danger: true,
   });
 
 /** The scope question for editing. */
 export const askEditScope = (event: CalendarEvent): Promise<EventScope | null> =>
   askScope(event, {
-    title: "Change this event?",
-    occurrenceLabel: "This occurrence",
-    occurrenceHint: "Applies to this date only.",
-    seriesLabel: "All occurrences",
-    seriesHint: "Applies to every date in the series.",
+    title: t("Change this event?"),
+    occurrenceLabel: t("This occurrence"),
+    occurrenceHint: t("Applies to this date only."),
+    seriesLabel: t("All occurrences"),
+    seriesHint: t("Applies to every date in the series."),
   });
 
 /**
@@ -57,7 +58,12 @@ export const askEditScope = (event: CalendarEvent): Promise<EventScope | null> =
 export function droppedMessage(dropped: string[]): string | null {
   if (!dropped.length) return null;
   const names = dropped.map((d) => d.replace(/^@/, "")).join(", ");
-  return `Saved for this date. ${names} ${dropped.length === 1 ? "applies" : "apply"} to the whole series and was left unchanged.`;
+  // One sentence per branch rather than a verb slot: which words agree with
+  // the count, and where they sit, is not the same in every language.
+  return plural(dropped.length, {
+    one: "Saved for this date. {names} applies to the whole series and was left unchanged.",
+    other: "Saved for this date. {names} apply to the whole series and were left unchanged.",
+  }, { names });
 }
 
 
@@ -80,9 +86,9 @@ export async function runScoped<T>(scope: EventScope, run: (scope: EventScope) =
   } catch (err) {
     if (scope !== "occurrence" || !isThisAndFutureRefusal(err)) throw err;
     const ok = await confirmDialog({
-      title: "This date cannot be changed on its own",
-      message: "It belongs to a change that was applied to this and all later occurrences, which the server will only edit as a whole. Apply to the entire series instead?",
-      confirmLabel: "Apply to series",
+      title: t("This date cannot be changed on its own"),
+      message: t("It belongs to a change that was applied to this and all later occurrences, which the server will only edit as a whole. Apply to the entire series instead?"),
+      confirmLabel: t("Apply to series"),
     });
     return ok ? await run("series") : null;
   }