## What changed
- Render transcript history and live output above the composer when `features.transcript_v2` is enabled and alternate-screen rendering is available. Handle scrolling, selection, copying, links, and older-history pagination in the main view.
- Add a clickable return-to-latest control with new-activity hints and temporary clipboard status. Let plain Enter return to latest when the composer is empty.
- Reflow retained transcript content during drawing and preserve the launch-selected screen mode across configuration reloads and session transitions, including `--no-alt-screen` restrictions.
- Enter the alternate screen with its first synchronized frame, and box CLI startup futures to reduce stack usage during session transitions.
## Testing
Add regression coverage for transcript layout, input routing, follow controls, clipboard status, and screen-mode persistence. Add a PTY test for the first alternate-screen frame and clean exit, and extend session-transition coverage through the CLI dispatcher.
GitOrigin-RevId: 1daf077826c7744b0f57399d10d159923dc87a97
## What changed
- Add mouse selection, word and line selection, drag autoscrolling, and keyboard selection with `Ctrl+Space`. Support copying selected text and opening links with a modified click.
- Anchor reading positions and selections to source text so resizing, streaming completion, and history pagination preserve the displayed content. Preserve hard line breaks, indentation, tabs, and graphemes when copying, while excluding display gutters and soft wraps.
- Rejoin activity groups split across history pages while retaining the reader's displayed revision.
- Distinguish confirmed clipboard writes from unconfirmed terminal requests, and retain native clipboard ownership after the transcript overlay closes.
- Manage mouse capture and keyboard modes across overlay transitions, editor handoffs, and suspend/resume.
## Testing
Add regression tests for selection during live updates and pagination, source-text copying across resize, clipboard confirmation and lifetime, and terminal mode restoration.
GitOrigin-RevId: 6b2438f576567cbba755b2405915a25acf009b8d
Eric Traut