Add support for the latest environments (add devnet, retire summit/w3s)

Summary

Add support for the latest environments in the CLI: add the new devnet preset, retire the removed summit / w3s environment, and keep the paseo naming unambiguous.

Background

The environment set changed. The summit environment was removed, and a new devnet preset was added. The reference for the exact values is contract-dependency-manager PR #61 (https://github.com/paritytech/contract-dependency-manager/pull/61).

Key facts from that change:

• devnet: the public products devnet on the Paseo testnet Asset Hub (para 1000, EVM chain id 420420417), wired to the community operated ContractRegistry at 0x59b0245778917af55224e5f8fb55f7f8d452619f. It uses the devnet-asset-hub / devnet-bulletin descriptors, the Bulletin RPC wss://bulletin-paseo.tservices.es:8443, and getChainAPI("devnet"). In CDM, cdm install -n devnet and cdm deploy -n devnet resolve against it.
• summit / w3s: removed upstream. This CLI currently carries a w3s preset that maps to the summit descriptors and endpoints (summit_asset_hub / summit_bulletin), and there is a two-name split where product-sdk calls the network summit while @parity/cdm-env and the CLI use the key w3s. All of that needs to be retired once the summit removal bump lands.
• paseo: the paseo preset targets paseo-next (para 1500); normalizeChainName already accepts the paseo-next-v2 / paseo-v2 aliases.

What needs to happen

• Add a devnet environment to the CLI so dot/playground commands can select it, resolving against the devnet registry and descriptors.
• Retire the w3s / summit preset and the cdmEnvName split once @parity/cdm-env drops summit. Track the @parity/cdm-env bump this depends on.
• Update normalizeChainName and any env registry so devnet is recognised and summit is gone.
• Refresh the env related notes in CLAUDE.md / docs-internal so the summit guidance is replaced with devnet.

Acceptance criteria

• dot init plus an install and a deploy work against devnet end to end.
• No summit / w3s path remains once the upstream removal lands.
• The paseo aliases still normalise correctly.