ui: добавить экспорт в CSV для сканирований и пакетов

- api/scans.py: добавить /api/v1/scans/export endpoint с фильтрами
- api/packages.py: добавить /api/v1/packages/export endpoint с фильтрами
- scans_list.html: добавить кнопку Export CSV в filter bar
- packages_list.html: добавить кнопку Export CSV в filter bar
- CSV включает все поля с правильным форматированием

guarddog_nexus/api/packages.py

@@ -1,6 +1,9 @@
 """REST API for packages (distinct packages across scans)."""
 
-from fastapi import APIRouter, Depends, Query
+import csv
+import io
+
+from fastapi import APIRouter, Depends, Query, Response
 from sqlalchemy import func, select, text
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -87,6 +90,54 @@ async def list_packages(
     }
 
 
+@router.get("/export")
+async def export_packages_csv(
+    flagged: bool | None = Query(None),
+    search: str | None = Query(None),
+    session: AsyncSession = Depends(get_session),
+):
+    subq = select(
+        Scan.package_name,
+        Scan.package_version,
+        Scan.ecosystem,
+        Scan.repository,
+        func.max(Scan.started_at).label("last_scanned_at"),
+        func.max(Scan.flagged).label("is_flagged"),
+        func.sum(Scan.total_findings).label("total_findings"),
+    ).group_by(Scan.package_name, Scan.package_version)
+
+    if flagged is not None:
+        subq = subq.having(func.max(Scan.flagged) == flagged)
+    if search:
+        pattern = f"%{search}%"
+        subq = subq.where(
+            Scan.package_name.ilike(pattern) | Scan.package_version.ilike(pattern)
+        )
+
+    subq = subq.order_by(func.max(Scan.started_at).desc())
+    rows = (await session.execute(subq)).all()
+
+    output = io.StringIO()
+    writer = csv.writer(output)
+    writer.writerow([
+        "name", "version", "ecosystem", "repository",
+        "last_scanned_at", "flagged", "total_findings"
+    ])
+    for r in rows:
+        writer.writerow([
+            r.package_name, r.package_version, r.ecosystem, r.repository,
+            r.last_scanned_at.isoformat() if r.last_scanned_at else "",
+            bool(r.is_flagged),
+            r.total_findings,
+        ])
+
+    return Response(
+        content=output.getvalue(),
+        media_type="text/csv",
+        headers={"Content-Disposition": "attachment; filename=packages_export.csv"},
+    )
+
+
 @router.get("/{name}/{version}")
 async def get_package(
     name: str,