Improve the chat input field

[pratikbuilds]

Before

The composer felt like a thin, detached text field. Typing a message or using commands introduced excess vertical space and pushed the controls away from the draft, so the whole surface looked unbalanced.

After

The input is now one full-width, bordered surface: the draft stays at the top and the actions remain anchored in a compact bottom rail. The keyboard shortcut appears only for a focused, non-empty draft, without creating extra padding. Attachment and send controls stay icon-only.

Verification

• bun test test/composer.test.tsx && bun run typecheck in packages/chat-ui
• bun run build in apps/web
• Browser-verified the focused, typed composer

bun run check is still blocked by an existing Hono 4.13.2/4.13.3 type mismatch in unchanged packages; dependency resolution was deliberately left out of this UI contribution.

[pratikbuilds]

Fresh browser capture of the current composer state after the latest input-surface refinement.

[TheGreatAxios]

critique · no blockers

The composer is now a full-width bordered column: draft on top, attach / Enter-to-send / send ArrowUp in a bottom rail. Hover-edit setText, Enter send, attachments, and send-disabled-while-sending all survive the merge onto current main. chat-ui composer tests pass.

Should-fix that landed on this branch before merge: the keyboard hint was opacity-only, so screen readers still announced “Enter to send” on an empty composer. Restored visibility: hidden plus aria-hidden until the draft is focused and non-empty.

Visual notes (not blocking): --ui-radius-lg is 0 in product so the box stays square; attach/send stay pills; focus is a --primary color swap rather than the old foreground inset hairline. Those match first-run composer more than the previous conversation row.

CI on this updated head (main merged in) is the merge gate.