retake v0.2.0

Added

• Dashboard. retake ui opens a local web UI to browse cassettes as readable conversations
  (OpenAI Chat Completions, OpenAI Responses and Anthropic Messages, including tool calls,
  thinking, streaming and token usage), view raw requests, responses and stream events, and
  delete stale interactions or cassettes.
• Live view. Every proxy serves the dashboard at /__retake/, streaming each call as it is
  replayed, recorded, passed through or unmatched, with the diff for unmatched calls.
• --open on record, replay and auto opens the live dashboard in a browser.

Changed

• Upstream names may no longer start with __, which is reserved for retake's own routes.

Security

• The dashboard API only answers requests addressed to localhost and requires a custom header
  for changes, so other websites can't read or modify cassettes. Pages are served with a strict
  Content-Security-Policy.