fix(plugin): prevent spinner garbage output in non-TTY environments

[MD-Mushfiqur123]

Issue for this PR

Closes#27908

Type of change

• Bug fix

What does this PR do?

When running opencode plugin install from non-interactive shells (PowerShell, CI/CD), the spinner animation outputs garbage — each frame (◓, ◑, ◒, ◐) appears on a new line because carriage returns are not interpreted in non-TTY environments.

The fix adds a createNonTTYSpinner() function that outputs plain text (msg... / msg done) instead of animated escape sequences when stdout is not a TTY.

How did you verify your code works?

• npx tsc --noEmit passes with no errors
• Pattern follows existing process.stdout.isTTY checks in the codebase (see packages/opencode/src/cli/ui.ts:49)

Checklist

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

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential duplicate PRs found:

1. fix(tui): prevent spinner garbage in non-TTY environments #29601 - fix(tui): prevent spinner garbage in non-TTY environments

   • fix(tui): prevent spinner garbage in non-TTY environments #29601
   • Addresses the same non-TTY spinner issue but for the TUI package

2. fix(opencode): avoid spinner noise in non-tty plugin install #28944 - fix(opencode): avoid spinner noise in non-tty plugin install

   • fix(opencode): avoid spinner noise in non-tty plugin install #28944
   • Directly targets plugin install spinner noise in non-TTY environments

3. fix: use static plugin spinner outside TTY #27951 - fix: use static plugin spinner outside TTY

   • fix: use static plugin spinner outside TTY #27951
   • Early attempt to fix the same plugin spinner TTY issue

All three PRs are addressing variations of the same core problem: spinner animation garbage output in non-TTY environments. You may want to check if these are already merged/closed or if there's overlap with the current PR #31529.

[github-actions]

Thanks for updating your PR! It now meets our contributing guidelines. 👍