[louis-bompart]

Description

This moves the repo onto the zod@4 package while keeping the Zod 3 API: every in-repo import … from 'zod' becomes import … from 'zod/v3', and every workspace depends on zod@^4.6.7, which ships the Zod 3 API at zod/v3. The code and the schemas don't change; only where they're imported from does.

Why

We want to move A2UI to Zod 4, starting with the basic catalog, without moving everything at once. That needs a single zod copy in the repo that offers both APIs.

A partial bump doesn't work. I tried bumping only @a2ui/web_core: it ends up with two copies of the Zod 3 types (3.25.76 and zod@4's zod/v3). Zod types are still part of web_core's public API, so tsc crashes (SIGABRT) or reports "Type instantiation is excessively deep" in every package that passes schemas to it. With a single copy, code can keep using zod/v3 and adopt Zod 4 from zod file by file.

What changed

• Imports: 103 source files, plus the schema generators (generate-zod-schemas, the catalog generators), now import from zod/v3. Regenerating the generated schemas changes nothing else.
• Dependencies: zod goes from ^3.25.76 to ^4.6.7 in web_core, Lit, Angular, React (dependency and peer), vegachart, mcp, tools/composer and samples/client/angular. The root resolutions pin moves to ^4.6.7, so third-party packages that accept Zod 4 share the same copy. Before, the pin forced them onto 3.25.76.
• Community samples: samples/community is a separate Yarn project that uses the published @a2ui/* packages, so it stays as it is. The two MCP sample clients bundle the in-repo mcp catalog, so their vite alias lists and tsconfig paths gain zod/v3, as they already had zod.
• Docs: 12 snippets in 9 READMEs and guides import from zod/v3.

Breaking change for consumers

Packages that take Zod schemas from their callers (web_core, the renderers, the catalogs) need those callers on the same zod@^4.6.7, importing from zod/v3. A caller still on Zod 3.25 gets a second copy of the types, and one writing import {z} from 'zod' with Zod 4 gets Zod 4 schemas, which these APIs don't accept yet. This is noted as BREAKING CHANGE in the changelogs of web_core, Lit, Angular, React, vegachart and mcp.

How it's tested

• From a clean build, yarn workspaces foreach -A -p --topological-dev run build and … run test pass in every workspace except one step, listed below. That covers web_core (1061 tests plus conformance), Lit, React, Angular unit and integration, markdown-it, vegachart, mcp, the agent SDK, the editor, inspector and shell tools, the samples and the specification tests.
• ESLint reports no errors in the touched packages.
• Prettier passes on every changed file except 11 Angular files, which were already unformatted on main.
• Not verified:
  • Angular test:closure-compiler, which needs Java 21. The machine I ran on has Java 8, so it fails before compiling.
  • samples/community, which isn't installed in this checkout.

Pre-launch Checklist

For this PR:

• I have updated the relevant CHANGELOG.md file.
• I updated/added relevant documentation.
• My code changes (if any) have tests. (Mechanical; covered by the existing suites.)
• If my branch is on a fork, I have verified that scripts/e2e_test.sh passes.

🤖 Generated with Claude Code

[louis-bompart]

Superseded by the regrouped stack on upstream main: this change is now part of #46 (series #45 to #54). The branch is kept for reference.