Close TS lint gap: either lint TypeScript or remove it

[EivMeyer]

There are .ts tests in tests/, but ESLint is not configured to lint TypeScript (no @typescript-eslint/* parser/plugin, and eslint . doesn’t include .ts by default).

Result: TS files can contain “lint disables” that do nothing (e.g. tests/live-streaming-jsonschema.test.ts:2), and TS code gets no pattern enforcement.

Tasks (pick one path)
A) Full TS linting

• Add @typescript-eslint/parser + @typescript-eslint/eslint-plugin.
• Update eslint.config.mjs with a TS files block (files: ['**/*.ts']) using the TS parser.
• Ensure npm run lint includes .ts (flat config should, once TS config exists; otherwise add --ext).

B) No TS in repo

• Convert/delete TS tests so lint + tooling is JS-only.

Acceptance

• Either TS is linted with strict rules, or TS is removed.

Refs

• tests/live-streaming-jsonschema.test.ts:2

[ByGamer01]

is it opened yet?