[Advancement] Ensure terminal UI meets accessibility contrast and screen-reader friendly output modes

[Nanle-code]

Objective

Audit and improve TUI/CLI output for accessibility, including non-color-only signals and screen-reader friendly modes.

Target area

ai_accessibility / output formatting

Context

Accessibility work exists in AI surfaces; extend principles to core CLI output.

Requirements

• Do not rely on color alone for errors/warnings
• Provide plain output mode suitable for screen readers
• Document accessibility options

Acceptance criteria

• Error/warning styling includes non-color indicators
• Plain mode tested
• Docs list accessibility flags

Pull request merge requirements

Pull requests that resolve this issue must not be merged until all of the following are true:

1. All required CI checks are green on the latest commit of the PR (build, tests, lint/format, and any workflow jobs required by branch protection).
2. The branch has no merge conflicts with the target branch (master / default), and a clean merge or rebase is possible without unresolved conflicts.
3. Review feedback is addressed, and the change remains focused on this issue’s acceptance criteria.

Contributors should run the local CI-equivalent checks before opening or updating the PR (see CI_ENFORCEMENT.md and CONTRIBUTING.md).

[Jumongweb]

@Jumongweb has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer, i will like solve this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Jumongweb to this issue.

[kitWarse]

Hello dear maintainer I have reviewed I can take it on