Chat input had `submitOnEnter` enabled while the comment editor used
`Mod+Enter`. Two consequences:
- Inconsistent muscle memory between the two inputs.
- In chat, bare Enter sending stole the only key that continues a
TipTap bullet/ordered list. Shift+Enter falls through to HardBreak
(a <br> inside the same list item), so bullet lists were stuck at
one item.
Drop `submitOnEnter` from the chat input so it follows the editor
default. Mod+Enter (⌘↵ / Ctrl+Enter) sends in both places; bare Enter
now continues lists and inserts paragraphs as users expect.
Surface the shortcut on the SubmitButton via a new optional `tooltip`
prop, and route the comment input through SubmitButton instead of an
ad-hoc Button — same affordance, deduped.
Add unit coverage for the submit-shortcut extension that pins
Mod-Enter, the submitOnEnter=false case, IME, and code-block guards.
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
Co-authored-by: multica-agent <github@multica.ai>