feat(connector): per-shot/version export folders, scene filter

Panel export paths now mirror the server's layout
({exportRoot}/{showId}/[{episode} if episodic]/{shotCode}/{version}) via a new
getShotExportDir helper, so farm and local renders land in the same folder.
Folder creation moves into the per-shot loop so one unwritable path no longer
aborts the whole queue.

Also adds an optional `scene` query param to the ext shots endpoint.

app/api/ext/projects/[projectCode]/shots/route.ts

@@ -18,6 +18,7 @@ function isAuthorized(req: NextRequest): boolean {
 //
 // Query params (all optional):
 //   episode   e.g. 108
+//   scene     e.g. 022
 //   sequence  e.g. 004
 //   status    e.g. IN_PROGRESS
 //   page      (default 1)
@@ -60,6 +61,7 @@ export async function GET(
       where: {
         projectId: project.id,
         ...(episode  ? { episode }  : {}),
+        ...(scene    ? { scene }    : {}),
         ...(sequence ? { sequence } : {}),
         ...(status   ? { status: status as never } : {}),
       },