Update dependencies in variables.yml

[brunopgalvao]

Summary

Bumps 12 dependencies flagged by the check-dependencies bot, in the central variables.yml.

Repositories:

• polkadot_sdk: polkadot-stable2603 → polkadot-stable2603-1 (Docker: stable2603 → stable2603-1)

Crates:

• subxt / subxt_cli / subxt_signer: 0.50.0 → 0.50.1
• polkadot_omni_node: 0.14.0 → 0.15.0

JavaScript packages:

• chopsticks: 1.3.0 → 1.3.1
• polkadot_api: 2.0.1 → 2.1.0
• resolc: 1.1.0 → 1.2.0
• hardhat_polkadot: 0.2.7 → 0.3.0
• solc: 0.8.34 → 0.8.35
• paraspell_sdk: 13.2.2 → 13.4.0
• hdkd_helpers: 0.0.29 → 0.0.30

Snippet line-number check

The embedded polkadot_sdk snippets — single-block-migrations/src/lib.rs, migrations/v1.rs (storage-migrations.md) and revive/src/precompiles/builtin/bn128.rs (eth-native.md) — are byte-identical between polkadot-stable2603 and polkadot-stable2603-1, so no snippet line ranges needed adjusting.

Companion PR

Test harnesses are synced in polkadot-developers/polkadot-cookbook#298. Live tutorial/recipe tests run there via the versions.yml CI triggers.

Test plan

• All target versions verified to exist (npm / crates.io / GitHub tag, HTTP 200)
• polkadot-stable2603-1 relay binaries (polkadot, *-worker, polkadot-parachain) resolve
• Embedded snippet files unchanged between tags (no line drift)
• variables.yml parses as valid YAML
• CI docs build + link checker (run on PR)

Not actioned — pinned to template lockfile (close as not-applicable)

#1667, #1668, #1669, #1670 — polkadot_sdk_parachain_template subdependencies are pinned to template v0.0.5's Cargo.lock and only change when the template version bumps (see comment in variables.yml).

Closes #1656, closes #1657, closes #1658, closes #1660, closes #1661, closes #1662, closes #1663, closes #1665, closes #1666, closes #1671, closes #1672, closes #1693