Upgrade TypeScript to 7 (build failing — needs review)

[woksin]

Summary

Upgrades the Samples repo to TypeScript 7.0.2 (the native compiler, current latest on npm), a drop-in for tsc/tsserver.

The TypeScript compiler/typecheck passes cleanly on both sample workspaces. However, the full yarn build (Vite) currently fails because a framework dependency (@cratis/arc.vite) uses the classic TypeScript programmatic API, which TS7's native package no longer exposes from its main entry. This is a dependency/tooling incompatibility, not a Samples code issue — see Blocker below.

Packages changed (old → new)

Package	Field	Old	New
root package.json	devDependencies.typescript	6.0.3	7.0.2

typescript is declared only in the root workspace. @types/*, @typescript-eslint/*, typescript-eslint, and rollup-plugin-typescript2 were intentionally left untouched.

Package manager

Yarn 4.5.3 (yarn workspaces, nodeLinker: node-modules). yarn install completes successfully. Note: yarn.lock is gitignored in this repo, so no lockfile appears in the diff.

Required accommodations for TS7 under Yarn

Two changes were needed for TS7 to install and typecheck — both are direct consequences of TS7's native packaging, not code changes:

1. Yarn builtin compat/typescript patch bypass — Yarn 4 unconditionally rewrites the typescript dependency through its builtin compat/typescript patch, which edits lib/_tsc.js / lib/tsserver.js / lib/typescript.js. The TS7 native package ships only lib/tsc.js + bin/tsc, so the patch fails with ENOENT. Added a tiny local Yarn plugin (.yarn/plugins/plugin-disable-typescript-compat.cjs, registered in .yarnrc.yml) that runs after the compat plugin and unwraps the builtin patch back to the plain npm descriptor.
2. baseUrl removal migration — TS7 removed the baseUrl compiler option (TS5102) and requires paths values to be relative (TS5090). Migrated tsconfig.json, Library/Lending/.frontend/tsconfig.json, and Library/Members/.frontend/tsconfig.json accordingly (removed baseUrl, prefixed paths values with ../).

Verification

• typescript resolves to 7.0.2 (native); node_modules/.bin/tsc --version → Version 7.0.2.
• tsc -b .frontend/tsconfig.json (full --force rebuild): PASS, zero errors, on both Library/Lending and Library/Members.
• yarn build (Vite): FAILS — see Blocker.

Blocker (needs review)

yarn build fails during Vite's transform step inside @cratis/arc.vite's EmitMetadataPlugin:

TypeError: Cannot read properties of undefined (reading 'fileExists')
    at parseTsConfig (@cratis/arc.vite/dist/esm/EmitMetadataPlugin.js)

Root cause: TS7's native typescript package exports only { version, versionMajorMinor } from its main entry — the classic programmatic API (ts.sys, ts.findConfigFile, ts.parseJsonConfigFileContent, …) moved to typescript/unstable/*. EmitMetadataPlugin does import ts from 'typescript' and calls ts.sys.fileExists, so ts.sys is undefined under TS7. This requires a TS7-native-compatible release of @cratis/arc.vite (and likely other TS-API consumers such as vite-tsconfig-paths and @typescript-eslint); it cannot be fixed within the Samples repo. The TypeScript bump and typecheck are otherwise green.

Workflow changes

None. grep of .github/workflows/ found no explicit typescript version pins or tsc install steps, so no workflow files were modified.

🤖 Generated with Claude Code

[woksin]

Draft: blocked only by @cratis/arc.vite's EmitMetadataPlugin (uses the TS programmatic API removed in TS 7) failing vite build. TS 7 port up in Cratis/Arc#2340; once published and the dependency is bumped here, this unblocks. Typecheck already passes on TS 7.