fix(opencode): handle cancel in upgrade process and customize spinner

[mortalYoung]

Issue for this PR

Closes #26154

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

The upgrade command had two issues:

1. Cancel not handled: When the user pressed Ctrl+C or dismissed the confirmation prompt, prompts.isCancel() was not checked. The cancelled value was falsy but only a bare !install check was used — this works incidentally but prompts.isCancel() should be checked explicitly to correctly handle the cancel signal returned by @clack/prompts.

2. Default spinner frames: The default spinner frames use characters in the range U+25D0–U+25D3 (◐◓◑◒), which are classified as "Neutral" width in the Unicode standard — meaning each font decides their rendered size independently. Many monospace fonts (Menlo, SF Mono, Fira Code, etc.) render these glyphs inconsistently: some frames appear slightly wider or taller than others, causing visible jitter in the animation. The Braille dot characters (⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏) are classified as "Narrow" width and render at a consistent single column width across fonts, producing a stable animation.

How did you verify your code works?

Tested locally by running bun dev upgrade, pressing Ctrl+C at the confirmation prompt and confirming it exits cleanly with "Done". Also verified the spinner renders correctly during the upgrade process.

Screenshots / recordings

N/A — CLI-only change, no UI.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

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[github-actions]

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[kowanietz]

I also experience the spinner jitter. Might be worth looking into centralizing it

[kowanietz]

This fixes the spinner jitter for upgrade, but I noticed other CLI commands still call prompts.spinner() directly. Would it make sense to move this spinner config into the existing helper for consistency?

[mortalYoung]

Ok. I defined createSpinner function and put it into a new file named prompt.ts as a result of I can't find an appropriate existing helper file.