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/lib/validations/managed-profiles.ts

@@ -15,6 +15,7 @@ import { z } from "zod/v4";
 
 import { isValidTimezone } from "@/lib/tz/format";
 import { isoDateTime } from "@/lib/validations/datetime";
+import { locales } from "@/lib/i18n/config";
 
 /**
  * The record's sex, as `User.gender` already stores it.
@@ -33,7 +34,7 @@ const managedProfileGenderSchema = z.enum(["MALE", "FEMALE", "OTHER"]);
 const managedProfileFields = {
   displayName: z.string().trim().min(1).max(DISPLAY_NAME_MAX_LENGTH),
   dateOfBirth: z.iso.date().nullable(),
-  locale: z.enum(["de", "en", "es", "fr", "it", "pl", "ko", "nl"]),
+  locale: z.enum(locales),
   timezone: z
     .string()
     .min(1)