feat(fc2c-i): showcase random-sample service and endpoint

backend/app/api/__init__.py

@@ -20,12 +20,14 @@ def all_blueprints() -> list[Blueprint]:
     from .import_admin import import_admin_bp
     from .ml_admin import ml_admin_bp
     from .settings import settings_bp
+    from .showcase import showcase_bp
     from .suggestions import suggestions_bp
     from .tags import tags_bp
     return [
         api_bp,
         gallery_bp,
         tags_bp,
+        showcase_bp,
         settings_bp,
         import_admin_bp,
         suggestions_bp,

backend/app/api/showcase.py

@@ -0,0 +1,23 @@
+"""Showcase API: scalable random sample of images."""
+
+from quart import Blueprint, jsonify, request
+
+from ..extensions import get_session
+from ..services.showcase_service import ShowcaseService
+
+showcase_bp = Blueprint("showcase", __name__, url_prefix="/api/showcase")
+
+
+@showcase_bp.route("", methods=["GET"])
+async def random_showcase():
+    try:
+        limit = int(request.args.get("limit", "60"))
+    except ValueError:
+        return jsonify({"error": "limit must be an integer"}), 400
+    async with get_session() as session:
+        svc = ShowcaseService(session)
+        try:
+            images = await svc.random_sample(limit=limit)
+        except ValueError as exc:
+            return jsonify({"error": str(exc)}), 400
+    return jsonify({"images": images})