feat(tui): add cursor style configuration

[dangooddd]

Issue for this PR

Closes #11738
Probably closes #1905

Also I found so many just closed issues and PRs about that feature:

• issue [FEATURE]: Non-blinking caret / cursor #5364
• duplicate issue [FEATURE] Make TUI cursor style configurable (thin/line cursor instead of forced block) #32209
• PR with that feature feat: add configurable cursor style for TUI textareas #11300
• another PR feat(tui): support configurable cursor style, blink, and color #16939 (strange PR, but...)

Type of change

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

What does this PR do?

This PR adds config options to style cursor in opencode and adds docs about this feature. opentui framework already supports this confuguration, so this PR does:

• adds new config option cursor, with fields style (line/block/underline/default), and blinking (boolean)
• all related components now use this config field (question, permission, dialog prompt, dialog export, dialog select and main prompt field)

It is really requested feature (many issues and PRs closed related to that, many commentators in open issues as well) so I think it will be nice to have.

How did you verify your code works?

Local test with bun dev (recordings in the section below). In video I configured opencode with project local config file .opencode/tui.json.

In video I show only main prompt, but I also tested:

• export dialog (/export)
• question tool from model
• select in input (/themes)
• command palette (ctrl + p)

Screenshots / recordings

2026-06-14.13-45-44.mp4

Checklist

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

[github-actions]

Hey! Your PR title TUI cursor style configuration (blinking, line/block/underline cursors) doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.