History navigation (↑/↓) scrolls line-by-line through multi-line prompts instead of jumping between entries

[berrat]

Describe the bug

When navigating prompt history with ↑ / ↓, multi-line prompts are traversed one line at a time rather than as a single entry. If a previous prompt is 30 lines long, pressing ↑ requires 30 keystrokes to pass through it and reach the entry before it. This makes history navigation for users who write long, detailed prompts effectively unusable.

Affected version

GitHub Copilot CLI 0.0.420.

Steps to reproduce the behavior

1. Submit a long multi-line prompt (10+ lines).
2. Submit another prompt after it.
3. Press ↑ in the empty input bar to navigate history.
4. Observe: the cursor moves through the long prompt one line at a time rather than jumping to it as a single unit.
5. You must press ↑ once per line of the previous prompt to navigate past it.

Expected behavior

↑ / ↓ in an empty input bar should jump between history entries as atomic units — the same behaviour as bash, zsh, fish, PowerShell, and every other shell. A 30-line prompt should be one ↑ press away, not 30.

When already inside a recalled multi-line prompt, ↑ / ↓ can navigate lines within it — but from an empty input, the first ↑ should always jump to the most recent entry in full.

Additional context

• OS: Windows 11 Pro (Build 26200 / 24H2)
• Shell: PowerShell 7.5.4
• Copilot CLI: 0.0.420 (win32-x64)
• Workaround: use Ctrl+G to open the recalled prompt in an external editor — but this shouldn't be necessary for basic history navigation.