Adds the zombienet-sdk storage-chain test module that exercises the full
storage-chain sync path against a pre-generated 100-block chain snapshot.

- `parachain_generate_db`: utility binary that submits 30 `store` extrinsics
  to a freshly-spawned parachain via the `Bob` authorization budget and cuts
  a `tip-sync-100.tgz` snapshot once both nodes finalize the target height.
- `parachain_tip_sync_with_renewals`: the main test; loads the snapshot,
  spins up a fresh full node, replays each store as a `renew_content_hash`
  extrinsic, and asserts the new node receives every renew payload over
  bitswap and matches storage roots with the producer.
- `fixture.rs`, `common.rs`: deterministic payload/algorithm/content_hash
  helpers and zombienet network setup shared by both binaries.
- `generate-snapshots.sh`: regenerates the 75MB `tip-sync-100.tgz` blob; the
  blob itself is downloaded from GCS at test time (not committed to git).
- `fixtures/*.json`: chain specs and snapshot metadata recorded alongside
  the snapshot.
- `full_node_warp_sync.rs`: small refactor to share the bitswap setup hook
  with the new storage-chain test.

`cumulus-zombienet-sdk-tests` gains the test as a binary target via the
`Cargo.toml` workspace entry.