backmerge 22-05-26 (next 16, alchemy key, hardhat v3)

[technophile-04]

Bundled backmerge of three upstream scaffold-eth-2 PRs:

• Deps: next 15 → 16 and minor frontend updates (Deps: next 15 → 16 and minor frontend updates scaffold-eth-2#1280)
• new Alchemy key (New Alchemy key scaffold-eth-2#1287)
• hardhat v3 migration (hardhat v3 migration scaffold-eth-2#1272)

Notes on the hardhat v3 migration (scaffold-eth#1272)

• Introduces rocketh (replacing hardhat-deploy's runtime) — new packages/hardhat/rocketh/{config,deploy,environment}.ts relocated into the hardhat template.
• hardhat.config.ts template rewritten to v3 defineConfig form: plugins, per-network type (http/edr-simulated), solidity.profiles, generateTypedArtifacts, and tasks: [overrideTask("deploy")...]. Exports etherscanApiKey (consumed by the new scripts/runVerify.ts).
• Hardhat package is now ESM ("type": "module"), uses @nomicfoundation/hardhat-toolbox-mocha-ethers, tsx, hardhat-deploy@^2, mocha, etc.
• tsconfig moves to node16 module/moduleResolution, es2022 target.
• Blockexplorer page (hardhat branch): build-info now filtered to .output.json and contract path prefixed project/contracts/. Foundry branch unchanged.
• Node ≥ 22.13 required by hardhat v3. Generated project engines set to >=22.10.0 (matching upstream) via the hardhat override; CI lint-instances.yml node bumped 20.x → lts/*. The templated project workflow already uses lts/*.

Local validation (node 22.20.0)

Generated a hardhat project and ran the full flow — all green:

• yarn compile ✓
• yarn test ✓ (2 passing)
• yarn deploy ✓ (contract deployed, deployedContracts.ts generated)
• yarn verify --help ✓ (etherscanApiKey import resolves)
• yarn hardhat:check-types / yarn hardhat:lint ✓
• yarn next:check-types / yarn next:lint ✓

Foundry project generation verified (shared blockexplorer template unaffected).

Test plan

• CI: hardhat / hardhat_with_extension jobs compile, deploy, lint, type-check on node lts/*
• CI: foundry / no_solidity_framework jobs still pass

[rin-st]

Working great for me!

[rin-st]

one suggestion - let's move this line to /rocketh/deploy.ts so we don't need to import it in every deployment file, as it is in the docs

export * as artifacts from "../generated/artifacts/index.js";

and then in deployment files just

import { artifacts, deployScript } from "../rocketh/deploy.js";

instead of

import { deployScript } from "../rocketh/deploy.js";
import * as artifacts from "../generated/artifacts/index.js";

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and one more thing, hh checks still stuck