i18n(pt): apply review round 2

Three-model review (astra, sol, fable), round 2: 29 of 30 findings
applied, one of them in part.

- pt: FIRMS «mais recente há», CCTV «cruzamentos», degraded radio
  directory, «{layers}: ativação recente» for any layer list, «Sem
  imagem», NIVELADO, AJUSTA-SE, quoted Provider Settings, V/S kept on
  the ADS-B card, no-break space in «(24 h)» / «(30 d)», and more
  (see docs/translations/pt.md).
- Malformed cyclone snapshot is now a catalog message (all locales).
- Markup supports data-i18n-context; the radio STATION TAG option uses
  "radio tag|All", so it no longer flips gender when the list loads.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/i18n/index.js

@@ -228,7 +228,9 @@ function normalizeMarkupText(text) {
  * Markup opt-in: the element's own English text or attribute is the source.
  *   <span data-i18n>Normal</span>
  *   <button title="Pin" data-i18n-title>…</button>
- * Also data-i18n-aria-label and data-i18n-placeholder.
+ * Also data-i18n-aria-label and data-i18n-placeholder. data-i18n-context
+ * gives the element's text a context, as t(text, { context }) does:
+ *   <option data-i18n data-i18n-context="radio tag">All</option>
  */
 const DOCUMENT_TRANSLATION_TARGETS = Object.freeze([
   ['data-i18n', null],
@@ -253,7 +255,10 @@ export function applyDocumentTranslations(doc) {
         ? element.getAttribute(attribute)
         : normalizeMarkupText(element.textContent);
       if (!source) continue;
-      const text = t(source);
+      const context = attribute
+        ? null
+        : element.getAttribute?.('data-i18n-context');
+      const text = context ? t(source, { context }) : t(source);
       if (text === source) continue;
       if (attribute) element.setAttribute(attribute, text);
       else element.textContent = text;