sky: store birth_tz, prefill form from User model, drop localStorage

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

src/apps/lyric/migrations/0019_sky_birth_tz.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0 on 2026-04-22 01:39
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('lyric', '0018_user_sky_fields'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='sky_birth_tz',
+            field=models.CharField(blank=True, max_length=64),
+        ),
+    ]

src/apps/lyric/models.py

@@ -52,6 +52,7 @@ class User(AbstractBaseUser):
     sky_birth_lat   = models.DecimalField(max_digits=9, decimal_places=4, null=True, blank=True)
     sky_birth_lon   = models.DecimalField(max_digits=9, decimal_places=4, null=True, blank=True)
     sky_birth_place = models.CharField(max_length=255, blank=True)
+    sky_birth_tz    = models.CharField(max_length=64,  blank=True)
     sky_house_system = models.CharField(max_length=1, blank=True, default="O")
     sky_chart_data  = models.JSONField(null=True, blank=True)