Support "zod/v3" from zod@4

[finom]

Closes #178

• Bump Zod version in root and other package.json files
• Replace "zod" imports to "zod/v3"
• Made sure that tests are passing
• Published a temporary version on npm under @finom/zod-to-json-schema name
• Tested in production, where schemas are emitted to files, git status says that nothing was changed after the upgrade

Demo: https://stackblitz.com/edit/node-d1uqmtku?file=index.js,package.json (run node index.js)

[aldex32]

Any chance to get this merged?

[ryoppippi]

we need to merge it for mcp sdk

[thucpn]

looking forward to this PR being merged