[CF deploy][human] Kid validation on cloud URL

[season179]

Agent tier

Human (HITL) — product validation, not code.

Blocked by

• [CF deploy][human] Custom domain + Worker route #200

Goal

Winni and Zack each complete at least one episode on the public cloud deployment.

Acceptance criteria

• Both kids can open https://typeling.digitalvanguard.xyz/ directly from Windows browsers.
• Typing, story unlock, audio sync, and scrub bar work on Windows browsers.
• Dad's Mac does not need bun run dev during play.

After success

• May deprecate legacy dev as primary in README (optional).

Scope note

• Zero Trust Access was intentionally disabled; this validation is for the public custom domain.