SEO: climate hub — collapse all countries by default, order alphabetically (#104)

Drop the open-by-default on the first three countries (every <details> starts
collapsed) and order the country sections alphabetically instead of by largest
city's population.

cities.py

@@ -58,12 +58,11 @@ def display_name(city: dict) -> str:
 
 def by_country() -> dict[str, list[dict]]:
     """Cities grouped by country (population-descending within each), country keys
-    ordered by their largest city — for the /climate hub's crawlable link graph."""
+    ordered alphabetically — for the /climate hub's crawlable link graph."""
     groups: dict[str, list[dict]] = {}
     for c in _load():
         key = c.get("country") or c.get("country_code") or "Other"
         groups.setdefault(key, []).append(c)
     for v in groups.values():
         v.sort(key=lambda x: -x["population"])
-    # order countries by their biggest city's population (most prominent first)
-    return dict(sorted(groups.items(), key=lambda kv: -kv[1][0]["population"]))
+    return dict(sorted(groups.items(), key=lambda kv: kv[0].lower()))

templates/hub.html.j2

@@ -12,7 +12,7 @@
      {{ n_cities }} cities across {{ n_countries }} countries. Every day is graded against that
      location's own ~45 years of climate history.</p>
   {% for country, cs in groups.items() %}
-  <details class="hub-country"{% if loop.index <= 3 %} open{% endif %}>
+  <details class="hub-country">
     <summary>{{ country }} <span class="hub-count">{{ cs | length }}</span></summary>
     <ul class="city-links">
       {% for c in cs %}<li><a href="{{ base }}/climate/{{ c.slug }}">{{ c.name }}</a></li>{% endfor %}