fix(cli): correct ajv import to resolve TypeScript build error

[0xAxiom]

What

Fixes a TypeScript compilation error in CLI/src/core/stages.ts caused by an incorrect AJV import pattern.

Before:

import Ajv from 'ajv';
// ...
const ajv = new Ajv.default({ allErrors: true, strict: false });

After:

import { Ajv } from 'ajv';
// ...
const ajv = new Ajv({ allErrors: true, strict: false });

Why

The default import import Ajv from 'ajv' combined with new Ajv.default() caused two TypeScript errors depending on which version of AJV types TypeScript resolved:

1. Property 'default' does not exist on type — when resolving against the root workspace node_modules/ajv (v6, which has no strict option and no .default subclass)
2. This expression is not constructable — when resolving against CLI/node_modules/ajv (v8 with dist/ built)

npm run type-check exited non-zero before this fix; it exits 0 after.

The named import { Ajv } correctly targets the exported class in AJV v8's type declarations (export declare class Ajv), removing both errors.

Also bumps ajv to ^8.20.0 (latest patch) which ships with a compiled dist/ directory, ensuring TypeScript resolves AJV v8 types rather than hoisting to the root workspace's AJV v6.

Tested

• npm run type-check passes (exit 0)
• npm run lint output unchanged (same 53 warnings, 0 errors)
• No behaviour change at runtime — the named and default imports resolve to the same class in Node.js

🤖 Generated with Claude Code