feat(E): add MediaAsset catalog — model, CRUD API, MediaBrowser UI

Migration 040: media_assets table with RLS (tenant_isolation + admin_bypass).
domains/media/: MediaAsset model, schemas, service, router with ZIP-download.
publish_asset Celery task in rendering/tasks.py.
core/storage.py: download_bytes() method for MinIO + LocalStorage.
frontend: MediaBrowser.tsx (grid/list, multi-select, zip-download, pagination) + api/media.ts.
Route /media (AdminRoute) + sidebar link with Image icon for admin+pm.

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

backend/app/domains/rendering/tasks.py

@@ -220,6 +220,44 @@ def render_turntable_task(
     }
 
 
+@celery_app.task(
+    name="rendering.publish_asset",
+    queue="step_processing",
+)
+def publish_asset(
+    order_line_id: str,
+    asset_type: str,
+    storage_key: str,
+    render_config: dict | None = None,
+) -> str | None:
+    """Create a MediaAsset record after a successful render."""
+    import asyncio
+
+    async def _run() -> str | None:
+        from app.database import AsyncSessionLocal
+        from app.domains.media.models import MediaAsset, MediaAssetType
+        from app.domains.orders.models import OrderLine
+        from sqlalchemy import select
+
+        async with AsyncSessionLocal() as db:
+            res = await db.execute(select(OrderLine).where(OrderLine.id == order_line_id))
+            line = res.scalar_one_or_none()
+            if not line:
+                return None
+            asset = MediaAsset(
+                tenant_id=getattr(line, "tenant_id", None),
+                order_line_id=line.id,
+                asset_type=MediaAssetType(asset_type),
+                storage_key=storage_key,
+                render_config=render_config,
+            )
+            db.add(asset)
+            await db.commit()
+            return str(asset.id)
+
+    return asyncio.get_event_loop().run_until_complete(_run())
+
+
 def _build_ffmpeg_cmd(
     frames_dir: Path, output_mp4: Path, fps: int = 30, bg_color: str = ""
 ) -> list: