Feature request: optional "Enter key behavior" - Enter inserts a newline instead of sending

[yumuq]

Summary

In the chat composer, plain Enter always sends the draft while Shift+Enter inserts a line break (hard-coded in ui-conversation's keymap). When drafting long or multi-line messages this makes composing awkward. This request is to add a General Settings preference - "Enter key behavior": Enter sends (current default) or Enter adds a newline - so users who prefer newline-style drafting can switch.

Proposed behavior

Mode	Enter	Shift+Enter	Cmd/Ctrl+Enter
Enter sends (default, unchanged)	send	newline	accelerated send
Enter adds a newline	newline	send	accelerated send

• IME composition is untouched: an Enter that closes a composition never sends or breaks the line.
• The existing "Enter behavior while busy" (queue/steer) keeps applying to whichever chord performs the plain send.
• Default mode is byte-for-byte the current behavior.

Status

A working implementation lives on branch feat/enter-key-mode in my fork (commit fa6b385f6a): durable enterKey setting, keymap routing, a shared settings row, zh/en copy, and tests (ui-conversation suite, lint, client typecheck all green). I'll open a pull request as soon as pull requests are enabled on this repository.

---

中文摘要：建议在通用设置中新增「回车键行为」开关，支持把 Enter 从"发送"切换为"换行"（此时 Shift+Enter 发送）；输入法组词与"繁忙时 Enter"语义不变。实现已就绪并推送到 fork 分支 feat/enter-key-mode，待本仓库开放 Pull Requests 后即可提交 PR。