docs: backfill changelog and document new keybindings

The Unreleased section listed 3 entries for 18 landed commits. Document the
TUI and CLI features from that batch, the fixes made alongside them, and the
new + and W keybindings in the README and keybindings guide.

Also stop tracking .playwright-mcp artifacts, which were committed by an
overly broad 'git add' during an earlier merge.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: c05ca230-fca3-43e4-9d78-c918bcba713e

Author: jongio