feat: implement solana-test-validator-up runtime installer

[ulissesferreira]

Summary

This PR is the second of two PRs splitting #8826, stacked on top of:

• feat: scaffold @metamask/solana-test-validator-up package #9209 — scaffold: feat: scaffold @metamask/solana-test-validator-up package

It contains only the real implementation of the Solana/Agave test-validator runtime installer, with no unrelated monorepo changes.

What's included (delta vs scaffold PR)

• src/install.ts — core Agave/solana-test-validator download, checksum verification, extraction, and install logic
• src/bin/solana-test-validator-up.ts — CLI entry point (registered as bin in package.json)
• src/index.ts — updated exports
• src/install.test.ts — Jest tests for the installer
• src/index.test.ts — removed (replaced by install tests)
• package.json — adds bin field + version bump
• CHANGELOG.md — changelog entry for the initial implementation
• README.md — full usage documentation
• jest.config.js — updated for the new test structure
• yarn.lock — updated for any new deps

What's NOT included

No knip.config.ts changes, no CODEOWNERS/teams.json churn (those are in the scaffold PR), no unrelated monorepo changes.

Replaces

Together with #9209, this replaces #8826 with two clean, reviewable PRs based on current origin/main.

Verification

yarn workspace @metamask/solana-test-validator-up run build
yarn workspace @metamask/solana-test-validator-up run test
yarn eslint packages/solana-test-validator-up
yarn constraints
yarn workspace @metamask/solana-test-validator-up run changelog:validate
yarn dedupe --check

All passed ✓

---

Note

Low Risk
New dev/CI tooling package with checksum-verified downloads and tests; no changes to wallet, auth, or production runtime paths.

Overview
Replaces the scaffold placeholder with a runtime-only installer modeled on @metamask/foundryup: it downloads a pinned Agave v3.1.14 release per platform, verifies SHA-256 checksums, extracts the archive into the MetaMask cache, and writes solana-test-validator and solana wrappers under node_modules/.bin. The harness is expected to start the validator and seed accounts; this package does not run Docker or a node.

Adds solana-test-validator-up CLI (install, default install, cache clean, --help) and exports the install API from src/index.ts. Cache location follows Yarn: YAML-parsed .yarnrc.yml enableGlobalCache selects ~/.cache/metamask vs repo .metamask/cache. Options merge from package.json (solanaTestValidatorUp and aliases), CLI flags, and defaults; partial release overrides shallow-merge platform maps instead of replacing pinned defaults. Missing package.json yields empty config so flag-only commands work.

Generated bin wrappers use spawnSync and exit non-zero when the child exits on a signal. Adds yaml dependency, broad install.test.ts, README/changelog, relaxed Jest coverage thresholds, and drops the greeter stub test.

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There are 3 total unresolved issues (including 2 from previous reviews).

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