[BUG] Claude Code (Claude Desktop app): IME composition Enter triggers submission in Plan inline comment and session rename inputs

Summary

In Claude Code running inside the Claude Desktop app, pressing Enter to confirm an IME (Japanese / CJK) conversion is incorrectly treated as a submit action in the following two input fields:

1. Plan mode inline comment input — the "Claudeへのコメントを入力..." (Enter a comment for Claude...) field that opens when you drag-select text in the plan body
2. Session rename input — the inline edit state that opens when you double-click a session name in the left sidebar

The main chat input and the AskUserQuestion "Other" free-text input were fixed in earlier patches. The same composition-aware Enter handling has not been propagated to the two surfaces above.

Steps to Reproduce

Case 1: Plan mode inline comment

1. In Claude Code (Claude Desktop app), enter Plan mode and receive a plan proposal
2. Drag-select text in the plan body to open the "Claudeへのコメントを入力..." (Enter a comment for Claude...) input field
3. Switch to a Japanese IME and type e.g. nihongo
4. Press Enter to confirm the IME conversion to 日本語

Expected: Enter only confirms the IME conversion; the comment stays editable.
Actual: Enter immediately submits the comment with partially converted / unintended text.

Case 2: Session rename

1. In Claude Code (Claude Desktop app), double-click a session name in the left sidebar to enter the rename edit state
2. Switch to a Japanese IME and type e.g. nihongo
3. Press Enter to confirm the IME conversion to 日本語

Expected: Enter only confirms the IME conversion; the rename field stays editable.
Actual: Enter immediately commits the rename with partially converted / unintended text.

Cross-check with AskUserQuestion

On the same build, AskUserQuestion's "Other" free-text input handles IME composition Enter correctly. The underlying fix exists in the codebase; it just has not been propagated to the Plan inline comment input and the session rename input.

Duplicate check vs. existing issues

The following related issues report the same class of IME Enter problem but target different UI surfaces, so they are not duplicates of this report:

| Issue | Target UI | State | Difference from this issue |
|---|---|---|---|
| #8405 | VS Code extension chat input | closed (fixed by PR #8480) | Different environment (VS Code extension) |
| #48257 | VS Code integrated terminal (xterm.js) | open | Different environment (TUI) |
| #42995 | claude.ai/code on Chrome | open | Different environment (Web) |
| #48209 | CLI slash-command input (Ghostty) | open | Different environment (CLI) |
| #36537 | Plan "Tell Claude what to do instead" input + AskUserQuestion Other | closed (author self-declared duplicate) | Different UI surface (the Revise popup, not the drag-initiated inline comment field). The AskUserQuestion part is verified fixed as of this report. |
| #30540 | Same Plan feedback input as above | closed, locked (dup of #8405) | Same as above — different UI surface |
| #27764 | AskUserQuestion "Other" | closed (NOT_PLANNED, stale) | Verified fixed in practice as of this report |

There are additional bug reports against the Plan inline comment feature and the session rename feature, but they concern comment delivery and rename persistence — unrelated to IME composition behavior — so they are excluded from this list.

No open issue currently covers the two UI surfaces reported here.

Environment

• Claude Code in Claude Desktop app, macOS
• Japanese IME