fix(terminal): preserve replay and history ownership

[Lint111]

Summary

• keep session selection in control of its buffer-load transaction across cached and canonical replay
• keep manually scrolled terminal history anchored until the reader actually returns to the bottom

Root causes

chunkedTerminalWrite() always finished the buffer-load gate, even when selectSession() supplied and still owned that gate. Live terminal output could therefore resume between restoration stages and interleave with a later replay.

Manual scroll protection also expired after 1.5 seconds. A busy Codex status redraw could reclaim the viewport while the user was still reading older output.

What changed

• nested replay uses the caller's owner token without beginning or finishing that transaction
• standalone replay retains its existing self-owned behavior
• upward wheel/touch scrolling locks the viewport
• writes preserve the exact xterm viewport while that lock is active
• downward scrolling releases the lock only after xterm reports the bottom

Commit structure

1. fix(terminal): retain session replay ownership
2. fix(terminal): keep manual history scroll anchored

Validation

• npx vitest run --config config/vitest.config.ts test/terminal-flush-budget.test.ts test/terminal-buffer-flush.test.ts test/codex-snapshot-replay.test.ts (19 tests)
• npm run typecheck
• npm run lint
• npm run check:frontend-syntax
• npm run check:public-assets
• npm run build
• Prettier and git diff --check

Scope

This PR does not include terminal streaming, warm-session caching, viewport ownership, keyboard layout settling, or authoritative frame capture.

[Ark0N]

Hi Lior, closing this one as part of a cleanup of the seventeen PRs currently open from you. The full explanation is in #173, and I would rather you read that one than this note, because it is the honest version and it is not a dismissal of your work.

The short form: sixteen PRs opened in a single day, roughly 42,000 added lines in total, landing mostly on the same few files (nine touch app.js, eight touch terminal-ui.js), with five already conflicting against master and none carrying CI results. I cannot review that at the standard this codebase needs, and merging it at a lower standard would be worse than not merging it.

Going forward, please keep no more than three open PRs at a time, each one a single behavior change that stands on its own, with a test that fails on master and passes with the fix. #214 and #215, merged today, are good models.

If this particular change fixes something that genuinely annoys you in daily use, it is a good candidate to be the first one you reopen on its own, rebased on current master. I will review it properly.

Thanks for the effort you put in, and sorry to close it this way.