docs(beta): open external validation intake before 1.0 #37

Goal

Give external beta users one safe, concrete path to validate CauseScope and return actionable evidence before stable 1.0.

Scope

• add a beta-testing guide covering install/live-lab paths, supported scope, and a scenario checklist
• document a minimal public TypeScript reproduction workflow
• route setup feedback to Discussions, reproducible defects to Issues, and sensitive/security reports to private channels
• add an explicit sanitization checklist for source, screenshots, URLs, state, requests, and trace exports
• link the guide from README, support, contribution, community, and docs navigation
• publish a GitHub Discussions announcement only after the guide is merged and live

Acceptance

• a new tester can run the live lab or current beta without repository knowledge
• the checklist covers ordinary text/source, decisions, state, props, network/storage, adapters, keyboard navigation, and trace export
• no workflow asks users to upload credentials, customer data, private source, or an unredacted trace
• the guide clearly states development-only/local-first scope and unsupported production monitoring
• docs build and full repository checks pass
• the public announcement links only to merged, live documentation