V1]individual] email tone rewriter

[clintjeff2]

Motivation

• Provide a folder-local UI surface for the Email Tone Rewriter tool that is accessible and isolated from the main app shell.
• Ensure the tool exposes idle, loading, error, and success states with keyboard and screen-reader affordances so future UI integration can import a stable local surface.

Description

• Added folder-local React components for the tool workflow: EmailToneRewriter, EmailToneRewriterEmpty, EmailToneRewriterLoading, EmailToneRewriterError, and EmailToneRewriterSuccess under tools/v1/individual/email-tone-rewriter/components.
• Added folder-local styling in tools/v1/individual/email-tone-rewriter/styles.css and a visual/accessibility doc in tools/v1/individual/email-tone-rewriter/docs/visual-style.md without modifying the shared design system.
• Exported the component surface from the tool public API by updating tools/v1/individual/email-tone-rewriter/index.ts to export * from "./components".
• Added component-level tests at tools/v1/individual/email-tone-rewriter/tests/components.test.ts that validate labeled regions, radio-group semantics, keyboard shortcuts, loading/error semantics, focusable success output, disabled action copy, and state routing.

Testing

• Ran git diff --cached --check which passed with no issues.
• Added unit tests (tools/v1/individual/email-tone-rewriter/tests/components.test.ts) and verification steps to run them with vitest, but executing bunx vitest in this environment failed while resolving test runner dependencies due to a registry 403 error so tests could not be completed here.
• All changes are contained in tools/v1/individual/email-tone-rewriter/ and component tests are included for CI to run in a network-enabled environment.

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Closes #351