feat(ui): bump thumbnail sizes 1.5x, make Settings fluid, add subscription_count stat

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/api/settings.py

@@ -6,7 +6,7 @@ from quart import Blueprint, jsonify, request
 from sqlalchemy import func, select
 
 from ..extensions import get_session
-from ..models import AppSetting, ImageRecord, ImportBatch, ImportSettings, ImportTask, Tag
+from ..models import AppSetting, Artist, ImageRecord, ImportBatch, ImportSettings, ImportTask, Tag
 
 settings_bp = Blueprint("settings", __name__, url_prefix="/api")
 
@@ -118,6 +118,9 @@ async def system_stats():
         storage_bytes = (
             (await session.execute(select(func.coalesce(func.sum(ImageRecord.size_bytes), 0)))).scalar_one()
         )
+        subscription_count = (await session.execute(
+            select(func.count(Artist.id)).where(Artist.is_subscription.is_(True))
+        )).scalar_one()
 
         # Task counts grouped by status
         status_rows = (
@@ -163,6 +166,7 @@ async def system_stats():
         "total_images": total_images,
         "total_tags": total_tags,
         "storage_bytes": storage_bytes,
+        "subscription_count": int(subscription_count),
         "tasks": {
             "pending": status_counts.get("pending", 0),
             "queued": status_counts.get("queued", 0),