fix(build): pin TypeScript to 5.9.x so the API bundle builds

[RubenHalman]

yarn workspace @orgcheck/api build fails on a clean install of main:

[!] TypeError: Cannot read properties of undefined (reading 'ES2015')
    at node_modules/@rollup/plugin-typescript/dist/es/index.js:528

orgcheck-api and orgcheck-sfdx-plugin declare "typescript": "^7.0.2", which resolves to TypeScript 7, the native rewrite. Its JS API no longer exposes ScriptTarget and ModuleKind the way @rollup/plugin-typescript@12.3.0 expects, so the plugin's module-kind validation reads undefined at import time. ts-jest@29 also caps at peer typescript ">=4.3 <7".

This pins both packages to the 5.9 line, the highest version both tools support.

Verified on macOS 26.5, Node 24.18, Yarn 4.18:

• dist/orgcheck.js and dist/orgcheck.d.ts are produced and the bundled test passes
• API suite 205/205, LWC jest 18/18
• the salesforce-app static resource builds from the new bundle and deploys unmanaged to a sandbox

One note that is out of scope here: on Yarn 4 the pack step that follows the rollup build still fails, because Yarn 4 names the tarball package.tgz while postpack moves orgcheck-api-*.tgz. That is independent of the TypeScript version and does not affect the bundle.