fix: Restore previous Avatar implementation as DeprecatedAvatar

[pawelgrimm]

Short description

Restores the previous Avatar implementation as DeprecatedAvatar while keeping the revamped Avatar export in place.

The deprecated component keeps legacy props such as user, avatarUrl, colorList, and responsive string sizes with scoped CSS module styles, and now lives in src/deprecated-avatar.

Restores the legacy Avatar stories under Deprecated Components/Avatar and moves the deprecated Input story into the same section.

PR Checklist

• Added tests for bugs / new features
• Updated docs (storybooks, readme)
• Reviewed and approved Chromatic visual regression tests in CI

[doistbot]

Thanks Paweł for safely restoring the legacy Avatar component to ease the migration path 😄 🙌.

Few things worth tightening:

• API conventions: Wrap the component in React.forwardRef and extend standard HTML div props (omitting style) so consumers can attach refs and standard attributes.
• Accessibility: Provide semantic markup for the image by either using an actual <img> tag or adding role="img" with a derived aria-label.
• Performance: Swap the root Box component for a plain div to avoid unnecessary responsive resolution overhead.
• Test coverage: Add a test exercising the restored colorList prop to ensure the legacy behavior is fully protected.

I also included a few optional follow-up notes in the details below.

Optional follow-up notes (4)

• [P3] src/deprecated-avatar/deprecated-avatar.test.tsx:7: The test suite is missing an accessibility test (jest-axe). Project guidelines mandate that every component should have an a11y test, even if this is a restored deprecated component.
• [P3] src/deprecated-avatar/deprecated-avatar.stories.tsx:103: Spreading ...args directly passes the story's userName and email keys as props to DeprecatedAvatar, which spreads them onto Box and ultimately the DOM div. This will trigger a React "does not recognize prop on a DOM element" warning in the console. Consider destructuring these properties out before spreading the rest of the arguments.
• [P3] src/deprecated-avatar/deprecated-avatar.tsx:67: colorList is currently typed as any string[], so colorList={[]} is a valid call. In that case emailToIndex(user.email, colorList.length) becomes ... % 0, which returns NaN and leaves backgroundColor unset, so the avatar can render white initials on no background. Guard the empty-array case here, or fall back to AVATAR_COLORS when colorList.length === 0.
• [P3] src/deprecated-avatar/deprecated-avatar.test.tsx:13: toMatchSnapshot() is locking the entire rendered node here, including Box's class composition, for a behavior that's really just “uses avatarUrl”. A focused assertion on backgroundImage/textIndent would cover the contract with less churn when unrelated markup or class details change.

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[doistbot]

🟡 P2 This suite never exercises the restored colorList prop, even though preserving that legacy API is one of the goals of this PR. Please add a case that passes a custom list and asserts the resulting backgroundColor, otherwise a regression here will slip through while the initials-only tests still pass.

[pawelgrimm]

Doistbot made some good points, but we're not reworking the avatar here, we're just bringing back the previous implementation under the "Deprecated" namespace.