fix(web): let paste expand a resting composer#9498

Note

Low Risk Localized chat input UX using the existing type-to-focus pattern and composer API; no auth, data, or backend changes.

Overview Fixes paste being dropped when the composer is in its resting (blurred) state after clicking the timeline—behavior that type-to-focus already handled for single keys.

Shared redirect rules: shouldRedirectInputToComposer centralizes the checks (editable/interactive targets, floating layers, defaultPrevented) so keyboard type-to-focus and the new paste path stay aligned. shouldTypeToFocusComposer now delegates to that helper after its key-specific guards.

Paste-to-focus: A capture-phase window paste listener runs when a thread is active and the same exclusions apply (command palette, terminal focus, open model picker). pasteTextToFocusComposer only handles plain text (skips file pastes for the composer’s own handler); on success it calls insertTextAtEnd, preventDefault, and stopPropagation so the composer focuses/expands like typing would.

^{Reviewed by Cursor Bugbot for commit 08346fbf4ff44eedabc513af9df049a3bbefa9d8. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Let paste events expand and focus a resting composer in ChatView

• Adds a shared shouldRedirectInputToComposer predicate that rejects default-prevented events, editable/interactive surfaces, and active floating layers; both type-to-focus and paste-to-focus use it
• Adds pasteTextToFocusComposer to accept plain-text clipboard events with no files, and a capture-phase window paste listener in ChatViewContent that inserts eligible text at the end of the composer and cancels default propagation on success
• The paste listener skips inactive-thread, command-palette, terminal-owned, and model-picker states
• Risk: paste events outside editable surfaces are now intercepted and cancelled when the composer accepts them; pasting into other custom listeners that rely on propagation may be affected

^{Macroscope summarized 08346fb.}