Merge upstream/main: air-quality layer (AQHI) meets i18n

Upstream's #568 adds the Air quality layer to the Weather group (ECCC
AQHI, Canada only) with a band legend, worst-first list and voice
support.

- package-boundaries: both sides' entries unioned.
- layerPanel/weatherPanel tests: both sides' new tests kept; the
  weatherPanel fixture follows upstream (legendCategorical: true, the
  'list' block id) while our localized-history (K-6) test stays.
- air-quality strings marked: band labels and the provider label as
  msg() data, the readings-list aria-label through t(); es/ru entries
  added (+6 keys each).
- The synthetic air-quality allocation-benchmark titles follow the
  file's own convention (// i18n-ignore) like TRK/VESSEL/CAMERA.

Also verified the auto-merged weatherPanel.js against upstream: ORDER
gains 'air-quality', OBSERVED stays slice(2, 5), and the data-driven
legendCategorical path is upstream's.

npm run i18n: complete (2559), no unmarked strings. npm test: only the
pre-existing environmental OPENAI_API_KEY leak fails. Build passes.

package.json

@@ -178,6 +178,7 @@
     "./layers/directions": "./src/layers/directions/index.js",
     "./layers/directions/source": "./src/layers/directions/source.js",
     "./layers/cctv": "./src/layers/cctv/index.js",
+    "./layers/air-quality": "./src/layers/airQuality/index.js",
     "./layers/alpr": "./src/layers/alpr/index.js",
     "./layers/radio": "./src/layers/radio/index.js",
     "./layers/submarine-cables": "./src/layers/submarineCables/index.js",
@@ -238,6 +239,7 @@
     "./layers/alpr/source": "./src/layers/alpr/source.js",
     "./layers/bikeshare/source": "./src/layers/bikeshare/source.js",
     "./layers/cctv/source": "./src/layers/cctv/source.js",
+    "./layers/air-quality/source": "./src/layers/airQuality/source.js",
     "./layers/earthquakes/source": "./src/layers/earthquakes/source.js",
     "./layers/perimeters/source": "./src/layers/perimeters/source.js",
     "./layers/gnss/source": "./src/layers/gnss/source.js",