feat: build client-side tabular Data Export capabilities (CSV / JSON format) for user records

[prakshithamalla-art]

Description

Closes #1487

This PR builds localized client-side data archive export utilities directly inside the authenticated dashboard user settings view to satisfy DevTrack's zero vendor lock-in commitments.

Changes Made

• Created a completely isolated, standalone component DataExportCard.tsx under the components layout folder.
• Configured real-time batch async endpoint fetching that aggregates both core user preferences and active milestone metrics structures simultaneously.
• Formatted structured raw memory serialization strings mapping JSON formatting buffers alongside flattened row-by-row delimited CSV lines.
• Triggered anchor-link transient browser download blobs (application/json & text/csv) entirely on the client, avoiding any unnecessary server database overhead.

[vercel]

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[github-actions]

GSSoC Label Checklist 🏷️

@Priyanshu-byte-coder — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[Priyanshu-byte-coder]

This PR now has merge conflicts with main. Please rebase your branch against the latest main and force-push to resolve. Run: git fetch upstream && git rebase upstream/main

[Priyanshu-byte-coder]

This PR has merge conflicts with the current main branch. Please rebase your branch onto main, resolve the conflicts, and force-push. Once conflicts are resolved and the PR is marked as mergeable it will be reviewed for merging.

[Priyanshu-byte-coder]

This PR has developed merge conflicts after recent merges to main. Please rebase onto the latest main branch, resolve all conflicts, and force-push. Once the PR is conflict-free it will be reviewed for merging.

[Priyanshu-byte-coder]

This PR has merge conflicts with the current main branch. Please rebase on the latest main to resolve them.

[Priyanshu-byte-coder]

CI is failing with two issues:

1. Outdated lockfile — The branch is based on old main before @emnapi/core/@emnapi/runtime were removed. Please rebase on main:

git fetch origin
git rebase origin/main
git push --force-with-lease

2. TypeScript errors in src/app/dashboard/settings/page.tsx — Multiple unclosed JSX tags and syntax errors (lines 600, 601, 635, 719, 891, 968, etc.). The JSX structure has mismatched tags that need to be fixed before CI can pass.

[Priyanshu-byte-coder]

CI is failing — settings/page.tsx has multiple JSX syntax errors:

settings/page.tsx(600,6): error TS17008: JSX element 'div' has no corresponding closing tag.
settings/page.tsx(601,8): error TS17008: JSX element 'div' has no corresponding closing tag.
settings/page.tsx(635,10): error TS17008: JSX element 'div' has no corresponding closing tag.
settings/page.tsx(719,12): error TS1381: Unexpected token. Did you mean `{'}'}` or `}`?
settings/page.tsx(891,13): error TS2657: JSX expressions must have one parent element.

(17+ errors total — unclosed tags and malformed JSX throughout the file)

Please fix all JSX syntax errors and make sure npm run type-check passes locally before pushing.

[prakshithamalla-art]

ill try to doit

[prakshithamalla-art]

it is doneecheck it and merge it

[Priyanshu-byte-coder]

This PR has merge conflicts with main due to recent changes. Please rebase to continue:

git fetch origin
git rebase origin/main

Once you resolve the conflicts and CI passes, we can review for merge.

[Priyanshu-byte-coder]

Hi! This PR has merge conflicts with the main branch. Could you please rebase or merge main into your branch to resolve them? We'd love to get this merged! 🚀

git fetch upstream
git rebase upstream/main
# resolve any conflicts
git push --force-with-lease

If you're no longer working on this, let us know and we can close it. Thanks!

[Priyanshu-byte-coder]

This PR has merge conflicts with the main branch. Please rebase your branch on latest main and resolve the conflicts so it can be reviewed and merged.