feat(i18n): register Brazilian Portuguese as a locale

Add pt-BR to the locale list and everything that hangs off it: the
client loader, Intl and date-fns mapping, the reply-language footers of
the Coach and insights prompts (English body, pt-BR footer, the same
path Korean and Dutch take), the citation-coverage normative words, the
no-key fallback copy, the AUDIT-C standard-drink line, country labels,
period search, CSV yes/no cells and the Telegram bare-word aliases.

The locale enums in the extract, managed-profile and record-settings
schemas now derive from the locale list instead of repeating it, and
the five notification and login-alert routes share one isLocale guard
instead of hand-rolled chains, so a later locale is one edit there.
A language tag is matched exactly and case-insensitively before its
primary subtag, so pt-BR and pt-PT browsers land on the Portuguese
bundle rather than English, and AUDIT-C no longer cuts a region tag to
two letters.

PHQ-9, GAD-7 and WHO-5 are not marked validated for pt-BR: the wording
has not been read against the published Brazilian forms, so readers get
the English items plus the existing note.

src/components/timeline/__tests__/timeline-rework.test.tsx

@@ -34,7 +34,17 @@ import { TimelineLegend } from "../timeline-view";
 import { useSeriesValueFormat } from "../use-series-value-format";
 import { item, wordsIn } from "./timeline-fixture";
 
-const LOCALES: Locale[] = ["de", "en", "es", "fr", "it", "pl", "ko", "nl"];
+const LOCALES: Locale[] = [
+  "de",
+  "en",
+  "es",
+  "fr",
+  "it",
+  "pl",
+  "ko",
+  "nl",
+  "pt-BR",
+];
 
 function render(node: React.ReactElement, locale: Locale = "en") {
   return renderToStaticMarkup(