playwriter@0.4.0

1. Cloud browser sessions via Browser Use — spin up stealth Chromium VMs in the cloud with playwriter session new --browser cloud. Supports residential proxies (--proxy us, --proxy de), custom proxies (--custom-proxy host:port), and configurable timeouts (--timeout 120). Idle sessions auto-disconnect after 10 minutes.

   New CLI commands:

   playwriter cloud login       # authenticate via device flow
   playwriter cloud status      # list active cloud VMs
   playwriter cloud subscribe   # open subscription page
   playwriter cloud live        # open live browser view

2. Headless browser mode — run without the extension or a visible browser:

   playwriter browser install                    # download Chrome for Testing
   playwriter session new --browser headless      # launch headless Chrome

   Multiple sessions share the same Chrome process with isolated contexts.

3. API key authentication for cloud browsers — skip the interactive device flow in CI and headless environments:

   export PLAYWRITER_API_KEY=pw_xxxxx
   playwriter session new --browser cloud

   Create and revoke keys at https://playwriter.dev/dashboard.

4. Fixed relay routing across Chrome profiles — two profiles signed into the same Google account no longer replace each other's relay connection.

5. Fixed cloud billing race conditions — concurrent cloud session requests now use durable per-org slot claims.

6. Fixed playwriter cloud login — uses Better Auth's current device authorization endpoints.

Fixes #80