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/migrations/0002_add_russian_fields.py

@@ -0,0 +1,38 @@
+# Generated by Django 6.0.3 on 2026-03-30 19:51
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('dailystone', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='mineral',
+            name='color_description_ru',
+            field=models.CharField(blank=True, max_length=300),
+        ),
+        migrations.AddField(
+            model_name='mineral',
+            name='description_ru',
+            field=models.TextField(blank=True),
+        ),
+        migrations.AddField(
+            model_name='mineral',
+            name='history_ru',
+            field=models.TextField(blank=True),
+        ),
+        migrations.AddField(
+            model_name='mineral',
+            name='name_ru',
+            field=models.CharField(blank=True, max_length=200),
+        ),
+        migrations.AddField(
+            model_name='mineral',
+            name='wikipedia_url_ru',
+            field=models.URLField(blank=True, max_length=500),
+        ),
+    ]