List and query block-volume snapshots in the active scope

Returns the block-volume snapshot inventory for the active tenant/subscription/project scope, loaded on the Snapshots page route. This single operation covers BOTH the plain route-load list (storage.snapshot.list) and the search/filter/sort/paginate behavior (storage.snapshot.search_filter_sort): both UI actions hit the same GET on this collection. Free-text q matches the snapshot name, source volume name, or snapshot id; the status filter (the All / Available / In progress / Error counter pills) AND-combines with it. Sortable columns include name and sizeGb. Each row carries the read model the table renders: name, status, source volume id+name, stored size vs. source volume size, incremental flag, encryption + KMS key, availability zone, child (derived) count, capture progress and createdAt. Validation: scopeId must resolve to a scope the caller can access (unknown or soft-deleted → 404 NOT_FOUND); status must be one of CREATING|AVAILABLE|ERROR; page ≥ 1 and pageSize within server bounds — any malformed filter/sort/pagination value → 422 VALIDATION_ERROR. RBAC: any scope role (owner|admin|contributor|reader|billing) may read. Async & state: Synchronous read; no state change. Capture progress (CREATING → AVAILABLE, progress 0→100) and failures (→ ERROR) arrive as resource.updated SSE frames with kind "storage.snapshot", not via this call. Errors: 401 missing/expired session; 403 authenticated but no role on the scope; 404 unknown scopeId; 422 malformed query parameter; 500 unexpected backend failure. Idempotency/Concurrency: Safe, cacheable; no idempotency key required. Repeated identical requests against the same read-model snapshot return identical pages.