[docs] Fix broken internal links in Apps docs

# [docs] Fix broken internal links in Apps docs

## Summary

Several internal documentation links point to routes that do not exist in the current docs tree. These links are reported by the repo's MDX linter as "Possibly broken internal link".

## Affected files

- `docs/apps/resources/templates.mdx`
- Line 74: `/mini-apps/growth/build-viral-mini-apps`
- Line 81: `/mini-apps/technical-guides/data-driven-growth`
- Line 88: `/mini-apps/growth/optimize-onboarding`
- `docs/base-account/guides/verify-social-accounts.mdx`
- Line 435: `/apps/introduction/overview`
- `docs/get-started/learning-resources.mdx`
- Line 21: `/apps/quickstart/create-new-app`

## Current behavior

These links do not resolve to existing `.mdx` or `.md` files in the repository.

## Expected behavior

The links should point to existing documentation pages, or the cards/references should be removed if the target pages no longer exist.

## How I found it

Ran:

```bash
node scripts/lint-mdx.js all
```

The linter reports these entries as possibly broken internal links.