rfc: review and split TUI-recording changes from PR #79 (shell_wait_for, submit, hold_last_ms, EADDRINUSE)

Tracking issue for PR #79 (`feat/claude-tui-recording`) so the work is captured without needing to review the code now.

PR #79 bundles four changes that came out of recording a real interactive Claude Code session with Shellwright (Ark OKF spike). Needs review before merge — flagging here because it should probably be split and/or grounded in an RFC rather than landing as one feature-first PR.

## What the PR does
- **`shell_wait_for` tool** — wait server-side until the terminal buffer matches `pattern`, does not match `absent_pattern`, and has been stable for `stable_ms`. Replaces client-side `shell_read` polling loops when driving TUIs. Overlaps with #82 (reads go stale / session undrivable).
- **`shell_send` `submit` option** — paste text, settle (`submit_delay_ms`, default 1s), then send Enter as a separate keystroke. Works around a trailing `\r` being swallowed by bracketed paste in chat TUIs.
- **`shell_record_stop` `hold_last_ms`** (default 2s) — hold the final GIF frame so the ending doesn't flash past on loop.
- **HTTP `listen` error handling** — `EADDRINUSE` previously crashed silently after the startup banner; HTTP mode now exits loudly, stdio mode warns.

Plus new doc `docs/recording-claude-code.md` and reference driver `docs/examples/drive-claude.mjs`.

## Open questions to resolve before merge
- Should `shell_wait_for` be its own RFC (like #51, #56, #18) rather than shipping inside a feature PR?
- Does `shell_wait_for` supersede / partially close #82?
- Split the four changes into separate PRs? (wait_for + submit are TUI-driving; hold_last_ms is recording UX; EADDRINUSE is a bug fix.)

Related: #82, #22.

Start by reviewing PR #79 and the related issues #82 and #22, then read the listed docs additions: docs/recording-claude-code.md and docs/examples/drive-claude.mjs. Resolve whether shell_wait_for needs its own RFC, whether the four changes should be split, and whether #82 is superseded; the work is done when those decisions are documented and the changes have a clear review path.

Written by the indexing model from the issue text.