docs: migrate guides from v1 to v2 Starlight

[mohith2883]

Description

Migrated the guides from v1 docs to v2 Starlight docs.

• Added the following guides under packages/docs/src/content/guides in .mdx format: • Background Removal
  • Image Optimization
  • Image Overlays
  • Image Underlays
  • Placeholders
  • Responsive Images
  • Social Media Cards
  • Text Overlays
  • Uploading Images and Videos

• Updated content to match Starlight syntax (.mdx, Tabs component, Callouts, etc.)

• Removed outdated redirect entries for guides from vercel.json.

Issue Ticket Number

Fixes #122

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Fix or improve the documentation
• [ ] This change requires a documentation update

Checklist

• [x] I have followed the contributing guidelines of this project as mentioned in CONTRIBUTING.md
• [x] I have created an issue ticket for this PR
• [x] I have checked to ensure there aren't other open Pull Requests for the same update/change?
• [x] I have performed a self-review of my own code
• [ ] I have run tests locally to ensure they all pass
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes needed to the documentation