feat: allow jumping forward and back between completed steps of stepper

[justEhmadSaeed]

Describe your changes

Closes #1088

Screenshots [Optional]

Screen.Recording.2025-07-24.at.7.23.21.PM2.mov

Issue ticket number and link

Checklist before requesting a review

• I have performed a self-review of my code
• I have added tests
• I have added a changeset pnpm changeset add
• I have added example usage in the kitchen sink app

[changeset-bot]

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Latest commit: 67da1c2

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[Copilot]

Pull Request Overview

This PR implements functionality to allow users to navigate between completed steps in a stepper component. The main change introduces a "max reached step" tracking mechanism that enables jumping back to previously completed steps while preventing forward navigation to incomplete steps.

• Adds state tracking for the maximum step reached by the user
• Updates step completion states and navigation controls based on user progress
• Includes example usage updates in the kitchen sink app

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/runtime/src/widgets/Stepper/Stepper.tsx	Implements max reached step tracking, updates step completion logic, and adds disabled state for unreachable steps
apps/kitchen-sink/src/ensemble/screens/widgets.yaml	Updates stepper example to show both icon and text in step template

[Copilot]

The completion logic is incorrect. A step should be marked as completed only if it's less than the max reached step, not less than or equal to it. The current step (index === maxReachedStep) should be active but not completed.

Suggested change

	<Step completed={index <= maxReachedStep} key={index}>
	<Step completed={index < maxReachedStep} key={index}>

[github-actions]

Visit the preview URL for this PR (updated for commit 67da1c2):

https://react-kitchen-sink-dev--pr1089-stepper-next-k6n0e050.web.app

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