Add Russian translations and pronunciation button

- Russian fields on Mineral model (name_ru, description_ru, history_ru, etc.)
- scrape_minerals_ru management command fetches from Russian Wikipedia via langlinks
- EN/RU toggle in header, saved to localStorage
- Speaker button next to mineral name uses Web Speech API
- Section headers and labels translated
- Russian Wikipedia link in footer when in RU mode

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

dailystone/admin.py

@@ -5,9 +5,9 @@ from .models import Mineral
 
 @admin.register(Mineral)
 class MineralAdmin(admin.ModelAdmin):
-    list_display = ('name', 'formula', 'day_of_year', 'color_hex', 'category')
+    list_display = ('name', 'name_ru', 'formula', 'day_of_year', 'color_hex', 'category')
     list_filter = ('category', 'crystal_system')
-    search_fields = ('name', 'formula')
+    search_fields = ('name', 'name_ru', 'formula')
     list_editable = ('day_of_year', 'color_hex')
     fieldsets = (
         (None, {
@@ -23,6 +23,10 @@ class MineralAdmin(admin.ModelAdmin):
         ('Text', {
             'fields': ('description', 'history'),
         }),
+        ('Russian', {
+            'fields': ('name_ru', 'color_description_ru',
+                       'description_ru', 'history_ru', 'wikipedia_url_ru'),
+        }),
         ('Links', {
             'fields': ('wikipedia_url',),
         }),