Add @b9g/zen/schema entrypoint for client-side usage

[brainkim]

Summary

Create a new entrypoint @b9g/zen/schema that exports table/view definitions without the database runtime. This allows tables to be used client-side for:

• Form validation
• API request/response contracts
• Shared types between client and server

Motivation

Tables are just Zod schemas with metadata. The database-specific code (drivers, queries, migrations) isn't needed for validation use cases.

Proposed Exports

// @b9g/zen/schema
export { z, table, view, isTable, isView, extendZod } from "@b9g/zen";
export type { Table, View, Row, Insert, Update } from "@b9g/zen";
// Possibly: FieldMeta, FieldDBMeta for form generation

Notes

• SQL builtins (NOW, TODAY, etc.) would still be available - they're just symbols
• No driver dependencies
• Smaller bundle for client-side usage

🤖 Generated with Claude Code