fix: use stable keys for list rendering (closes #990)

[Aashita101]

PR Description

The Card components inside ActivityOverview.tsx were using array indices as React key values. This PR replaces index-based keys with stable identifiers (item.pb_recordId / fallback to item._id) to fix reconciliation issues and prevent unnecessary UI glitches.

Type of Change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update

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• Frontend
• Backend
• Documentation
• Others

Related Issue

SB2318#990

Add your Work Example

No visual change — this is a performance/reconciliation fix. Console warnings for unstable keys are now resolved.

Fixes (mention the issue number which this fixes)

#closes 990

Checklist

• I have updated my branch and synced it with the project's 'develop' branch before making this PR.
• I have optimized the file changes.
• I have added a snapshot of my work example.
• I have made a PR to the project's develop branch.

Undertaking

• My code follows the style guidelines of this project.

• I have performed a self-review of my code.

• I have commented my code, particularly in hard-to-understand areas.

• I have made corresponding changes to the documentation.

• I have checked for plagiarism and assure its authenticity.

• I have read and followed the code of conduct for this repository. I understand that violation of this undertaking may have legal consequences.

• I Agree

[SB2318]

@Aashita101, please try to create a PR on our repository.

[Aashita101]

Hi @SB2318! I've created the PR on your repository — #1107. Please check it out!