[UM-CLONE-5] Steel-Browser — session record/replay + proxy abstraction

[Delqhi]

Source

• Project: Steel-Browser
• License: Apache-2.0
• Clone mode: code

Feature we want

First-class session lifecycle (create/resume/destroy), built-in recorder/replay, proxy rotation abstraction.

Why we want it

Pairs perfectly with our forensic-replay hero feature. Session API is the missing user-facing surface around our HAR+trace bundle.

Acceptance criteria

• SessionManager class with create/resume/destroy/list
• Recorder writes to our existing bundle format (HAR+trace+screenshots)
• Replay subcommand unmask replay <session-id>
• Proxy abstraction with rotating-proxy adapter interface
• Integration test: record → replay → assert identical DOM
• PR body cites source repo + commit SHA + license
• THIRD_PARTY_NOTICES.md updated
• Parity test added (proves our clone behaves like source for the relevant case)
• CHANGELOG entry: cloned from Steel-Browser@<sha>

Reference

See COMPETITIVE_STRATEGY.md for the full doctrine.