Issue 14 improve error handling

[SuchetaVadakkepat10]

Description

This PR focuses on improving the error handling mechanism by the following ways:

• Added custom error classes with proper HTTP status codes (BadRequestError, NotFoundError, etc.)
• Implemented validation functions for file uploads (size, format, filename) and job requests
• Added try-catch blocks to all API endpoints with consistent JSON error responses
• Enhanced file upload validation with size limits (100MB) and supported formats (.mp4, .avi, .mov, .mkv, .wmv)

Related Issue

This PR address #14

Type of Change

• Bug fix
• New feature
• Enhancement
• Documentation
• Other (please specify)

How Has This Been Tested?

All the error logging mechanism was tested with Postman; the API endpoints were tested using valid and invalid inputs.

• File upload validation: Tested with unsupported formats, empty files, and missing video field
• Job ID validation: Tested with invalid UUIDs, non-existent job IDs, and malformed requests
• API endpoints: Verified all endpoints return proper HTTP status codes (400, 404, 413, 415, 500)

Screenshots (if applicable)

Checklist

• My code follows the project’s style guidelines
• I have performed a self-review of my code
• I have commented my code where necessary
• I have added/updated tests (if applicable)
• Documentation has been updated (if needed)