Add daily-stone page showing a different mineral each day

New dailystone app with 207 minerals scraped from Wikipedia.
Each day displays a different mineral with photos, formula,
properties, description, and history. Page theme color matches
the mineral's typical appearance.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dailystone/views.py

@@ -0,0 +1,28 @@
+from datetime import date
+
+from django.shortcuts import render, get_object_or_404
+
+from .models import Mineral
+
+
+def daily_stone(request):
+    today = date.today()
+    day = today.timetuple().tm_yday
+    total = Mineral.objects.count()
+
+    if total == 0:
+        return render(request, 'dailystone/stone.html', {'mineral': None})
+
+    # Wrap around if we have fewer minerals than days in the year
+    index = (day - 1) % total + 1
+    mineral = Mineral.objects.filter(day_of_year=index).first()
+
+    # Fallback: pick by modulo of pk list
+    if not mineral:
+        minerals = list(Mineral.objects.all())
+        mineral = minerals[(day - 1) % len(minerals)]
+
+    return render(request, 'dailystone/stone.html', {
+        'mineral': mineral,
+        'today': today,
+    })