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/urls.py

@@ -0,0 +1,9 @@
+from django.urls import path
+
+from . import views
+
+app_name = 'dailystone'
+
+urlpatterns = [
+    path('', views.daily_stone, name='daily_stone'),
+]