[Feature] [Studio] Enhance rendering flow, pagination, and export handling

[Gautam25Raj]

Summary

This PR enhances the cover letter rendering pipeline by introducing structured flow content types, reusable content builders, and improved pagination handling across PDF and web rendering systems.

The update also improves hidden section handling and expands test coverage for cover letter exports.

Features

Cover Letter Flow System

• Added CoverLetterFlowContent type for structured content generation
• Introduced ProfessionalFlowItem type for standardized rendering flows
• Improved content organization and rendering consistency

Content Generation

• Added reusable functions for building cover letter content
• Introduced weighted pagination helpers for content distribution
• Improved layout generation across multi-page documents

Rendering Enhancements

• Refactored VeriWorkly PDF templates to use shared flow builders
• Refactored VeriWorkly web templates to use shared flow builders
• Improved consistency between PDF and web rendering outputs

Improvements

Export Handling

• Improved handling of hidden sections during exports
• Enhanced conditional rendering behavior for cover letter templates
• Increased consistency between editor previews and exported documents

Testing

• Added test coverage for:
  • Hidden section rendering
  • Export behavior
  • Link rendering in cover letters
• Improved reliability of cover letter generation workflows

Architecture

• Simplified rendering logic through shared flow utilities
• Improved maintainability and extensibility of cover letter systems
• Enhanced consistency across rendering pipelines

Notes

• No breaking changes
• Focused on cover letter rendering quality, pagination, and export reliability

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)
• 📝 Documentation update
• 🧪 Tests (adding or updating tests)

Checklist

• I have read the CONTRIBUTING.md document.
• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• Any dependent changes have been merged and published in downstream modules.