feat: add a generated api client

[joshsny]

Right now, half the work for adding tools is adding the schema from the API.

Our OpenAPI spec is far from perfect, and we can't rely on it for our API client, but it does have some useful types that we can generate a client from and use within our own API client.

This adds a generated client and uses it for the insights().list() method as an example.

[Copilot]

Pull Request Overview

This PR adds a generated API client by introducing a new OpenAPI-based client generation system that works alongside the existing manual API client implementation.

Key changes:

• Adds automated OpenAPI client generation from PostHog's API schema
• Integrates the generated client into the existing ApiClient class
• Updates the insights API endpoint to use the new generated client as a proof of concept

Reviewed Changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
typescript/src/api/fetcher.ts	Implements a custom fetch adapter for the generated API client with authentication and parameter handling
typescript/src/api/client.ts	Integrates the generated client and updates insights list method to use it
typescript/scripts/update-openapi-client.ts	Provides automation script to fetch OpenAPI schema and generate TypeScript client
typescript/package.json	Adds new dependencies and npm script for client generation
biome.json	Excludes generated TypeScript files from linting

Files not reviewed (1)

• typescript/pnpm-lock.yaml: Language not supported

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[jonathanlab]

LGTM, definitely better than nothing 👍🏻