docs: add self-hosted TypeScript examples

[lntutor]

Summary

• pair the self-hosted server, credential, and multi-exchange Python snippets with TypeScript examples
• use the TypeScript SDK's actual public credential keys (apiKey and privateKey)
• correct the configuration table's stale TypeScript credential aliases
• regenerate docs/llms-full.txt
• add a regression test for the documented TypeScript paths

This change was AI-assisted and manually verified against ExchangeOptions, the Kalshi and Smarkets authentication adapters, and the server namespace exports.

Closes #1920

Verification

• npm run docs:llms
• npm test --workspace=pmxt-core -- --runInBand core/test/unit/docs-copy-paste-samples.test.js core/test/unit/llms-docs.test.js
• git diff --check

Node.js 20.19.2 was used for the checks.