fix(i18n): extract navigation links module and restore verbatim pt footer

- Move getLocalizedHref, LOCALES, and CANONICAL_ROUTES to i18n/links.js to resolve SSR 500 error on home
- Import from @/i18n/links in page.jsx, Header.jsx, Footer.jsx, and LanguageSelector.jsx
- Restore exact production footer texts, author links, and SVG icons in pt
- Verify 100% visible text parity on all pt pages against production with cmp-pt.py

Co-Authored-By: Antigravity <noreply@google.com>

app/[locale]/page.jsx

@@ -5,7 +5,7 @@ import Link from "next/link";
 import seriesData from "@/public/series.json";
 import frameworksData from "@/public/frameworks.json";
 import { SITE } from "@/lib/seo";
-import { getLocalizedHref } from "@/components/LanguageSelector";
+import { getLocalizedHref } from "@/i18n/links";
 import {
 	AlertTriangle,
 	ArrowRight,