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/ui/templates/context.html

@@ -122,7 +122,7 @@
               <button id="radio-enable-btn" class="panel-layer-toggle" type="button" aria-pressed="false" data-i18n>ENABLE</button>
               <label class="radio-filter-label" for="radio-filter" data-i18n>STATION TAG</label>
               <select class="gev-field" id="radio-filter" aria-label="Filter stations by station tag" disabled data-i18n-aria-label>
-                <option value="all" data-i18n>All</option>
+                <option value="all" data-i18n data-i18n-context="radio tag">All</option>
               </select>
             </div>
             <div id="radio-station-card" class="radio-station-card" aria-live="polite">