fix: resolve showcase page crash caused by undefined isDark prop

[pericharlabindhumadhavi-data]

Description

Fixed the dark/light theme rendering issue on the Showcase page.

The problem occurred because theme-related styling and the isDark prop handling were inconsistent inside the Showcase components, causing incorrect rendering behavior and runtime issues in some cases.

Fixes #1501

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Type of Change

• Bug fix (non-breaking change that fixes an issue)
• UI/UX improvement (design, layout, or styling updates)

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Changes Made

• Fixed theme rendering issues on the Showcase page
• Corrected isDark prop handling in Showcase components
• Improved dark/light mode background and text rendering
• Cleaned up Showcase page styling for consistent appearance

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Dependencies

• No new dependencies added
• No version updates required

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Checklist

• My code follows the style guidelines of this project.
• I have tested my changes across major browsers and devices
• My changes do not generate new console warnings or errors.
• I ran npm run build and attached screenshot(s) in this PR.
• This is already assigned Issue to me, not an unassigned issue.

##Screenshots / Demo
Before
Showcase page crashed due to undefined isDark prop.
https://github.com/user-attachments/assets/712da467-7587-4cf0-95e9-ad276d0399e2

After
Showcase page renders correctly without runtime errors.
Theme/layout works properly after removing the undefined reference.
https://github.com/user-attachments/assets/d280cedc-696c-414e-8b70-6b5c1eb58fbb

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[github-actions]

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[github-actions]

✅ Synchronized metadata from Issue #1501:

• Labels: level 1, recode
• Milestone: recode:launch 3.0