fix(postinstall): read the download opt-out from workspace apps in monorepos

[hryhoriiK97]

Problem

The postinstall read the enriched-markdown block only from INIT_CWD/package.json. In a pnpm or yarn workspace that is the repo root, which normally has no block. An app that set "enriched-markdown": { "enableMath": false } in its own package.json still downloaded RaTeX at install time, while the podspec and gradle honoured the same block for the build. The docs told people to put the block in the app's package.json, so in monorepos the download opt-out silently did nothing.

Seen in T3 Code (apps/mobile opts out of math, root has no block).

Change

• postinstall.mjs reads the block from INIT_CWD as before. When that package.json has no block, it lists workspace members from npm/yarn workspaces and from the packages: list of pnpm-workspace.yaml, keeps the ones that depend on this package, and skips an asset only when every one of them opts out. A root block still wins.
• The lookup lives inside postinstall.mjs on purpose. Downstream forks pack the postinstall by file name (T3's pack-t3.mjs copies an explicit list), so a sibling module would silently go missing from their tarball and crash the install. A --resolve-config flag prints the lookup result and exits, for tests and debugging.
• No behaviour change for single apps or roots that already carry the block.
• Docs: the "Which package.json?" paragraphs describe the fallback, plus a note on pnpm's sideEffectsCache, which reuses postinstall output across projects regardless of the consumer's block.

Tests

Unit (__tests__/consumer-config.test.ts, 13 cases, full suite 103 passing). Each case spawns the real postinstall.mjs --resolve-config against a temp workspace: root block wins over members, pnpm workspace fallback, yarn workspaces array and object forms, mixed opt-outs keep the download, members that do not depend on the package are ignored, no consumers, malformed JSON, glob expansion (*, **, node_modules and dot dirs skipped), negated patterns subtract and cannot veto an opt-out, pnpm YAML with comments, quotes and flow style, peerDependencies consumers, and flag merging that skips non-boolean keys.

End to end with pnpm 11.10.0: packed the library with yarn pack (prepack included), then installed the tarball via file: into two throwaway workspaces shaped like T3's (root without a block, apps/* in pnpm-workspace.yaml, the allowBuilds entry, sideEffectsCache: false so each postinstall really ran).

Workspace	apps/mobile block	Postinstall log	ios/vendor/RaTeX.xcframework	grammars
fix	enableMath: false	math disabled via package.json … skipping RaTeX	absent	present
control	none	fetches RaTeX v0.1.14	present	present

Also ran the postinstall against a copy of T3 Code's real root package.json, pnpm-workspace.yaml and apps/mobile/package.json: RaTeX is skipped. The branch merges cleanly into fork/t3-mobile (git merge-tree), whose postinstall.mjs is identical to main's.

🤖 Generated with Claude Code

[eszlamczyk]

Overall good, the lack of !… (and test asserting behaviour that looks incorrect to me are blockers, everything else is a nitpick (approving though as they will not explode anything but I'd like it addressed)