test(terminal): pin a Japanese conversion-segment key against the Enter predicate

Shift+Left/Right resizing the conversion segment is a standard Japanese IME
operation, and on Windows it arrives mid-composition as Process/229 with Shift
held — the same shape as a shifted jamo, and the same rewrite into Enter.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HL8CxXZYghUKJEQpYhKeGg

src/renderer/src/components/terminal-pane/terminal-ime-deferred-newline.test.ts

@@ -355,7 +355,9 @@ describe('isTerminalImeProcessEnter', () => {
     { altKey: true },
     // Windows hands every IME-consumed keydown the same Process/229 shape, so a shifted
     // jamo (ㅃ on KeyQ) differs from the committing Enter only by `code`.
-    { code: 'KeyQ' }
+    { code: 'KeyQ' },
+    // Same shape from a Japanese IME: Shift+Left/Right resizes the conversion segment.
+    { code: 'ArrowLeft' }
   ])('rejects a non-IME or ambiguous Process key', (override) => {
     expect(isTerminalImeProcessEnter(event(override))).toBe(false)
   })