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.

.github/ISSUE_TEMPLATE/translation.yml

@@ -1,16 +1,16 @@
 name: Translation feedback
-description: Report a wording, grammar, or register problem in HealthLog's AI-initial locales (FR / ES / IT / PL / KO / NL).
+description: Report a wording, grammar, or register problem in HealthLog's community-maintained locales (FR / ES / IT / PL / KO / NL / PT-BR).
 title: "[Translation] "
 labels: ["i18n", "translation-feedback"]
 body:
   - type: markdown
     attributes:
       value: |
-        HealthLog ships German and English as maintainer-curated translations. French, Spanish, Italian, Polish, Korean, and Dutch ship as **AI-initial translations** — the prose passes the locale-integrity test (full key parity, no empty values) but has not been hand-reviewed for register or regional vocabulary.
+        HealthLog ships German and English as maintainer-curated translations. French, Spanish, Italian, Polish, Korean, Dutch, and Brazilian Portuguese ship as **AI-initial, community-maintained translations** — the prose passes the locale-integrity test (full key parity, no empty values) but has not been hand-reviewed for register or regional vocabulary.
 
         This template captures concrete fixes you would like to see. Phrasing nuance, regional vocabulary (e.g. "Tú" vs "Usted"), gendered forms, and domain-specific health terms are all in scope. The maintainer applies fixes during the regular release cycle.
 
-        For wholly new locale requests (e.g. "please add Portuguese"), open a [Discussion](https://github.com/MBombeck/HealthLog/discussions) instead.
+        For wholly new locale requests (e.g. "please add Swedish"), open a [Discussion](https://github.com/MBombeck/HealthLog/discussions) instead.
   - type: dropdown
     id: locale
     attributes:
@@ -22,6 +22,7 @@ body:
         - Polish (pl)
         - Korean (ko)
         - Dutch (nl)
+        - Brazilian Portuguese (pt-BR)
         - Other (specify under "Surface")
     validations:
       required: true