feat(web): edit the last queued message with Option+Up

[jakeleventhal]

Screen.Recording.2026-09-19.at.10.49.56.AM.mov

Editing a queued message needed a mouse trip to its pencil button. There was no keyboard shortcut for it.

This adds a thread.editQueuedMessage keybinding, bound to alt+arrowup when the composer has focus. It opens the most recently queued message in the composer, the same as clicking its pencil button, and expands the queue list if it was collapsed. The shortcut can be changed in Settings → Keybindings, and existing configs pick up the new default automatically.

The shortcut only fires when the caret is at the very start of the draft with nothing selected, which includes an empty composer. Anywhere else, Option+Up still moves the caret natively. Pressing it from inside the first paragraph moves the caret to the start first, and a second press opens the queued message. It also stands aside while a queued message is already being edited. The edit button's tooltip on the last queued row shows the shortcut, and the composer user guide mentions it.

Covered by the keybinding resolution and settings tests, and tested by hand on a dev server (recording above).

Opus 5 (1M context) via Claude Code in T3 Code.

🤖 Generated with Claude Code

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This adds a new user-facing queued-message editing workflow and changes DEFAULT_KEYBINDINGS so existing users receive a new Option/Alt+Up behavior by default. The implementation is contained and tested, but the product-default change requires human review.

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