Add multipart file upload endpoint for more efficient CV analysis

[coolbung]

Added new /analyze-upload endpoint that accepts multipart/form-data:

Benefits over base64 endpoint:

• 33% smaller payload (no base64 encoding overhead)
• More memory efficient
• Industry standard for file uploads
• Better performance for large files

Features:

• Direct file upload with multipart/form-data
• JSON configuration in form fields
• File type validation
• Maintains backward compatibility (old endpoint still works)

Both endpoints now available:

• POST /api/v1/analyze - Base64 JSON (existing, for Frappe integration)
• POST /api/v1/analyze-upload - Multipart upload (new, more efficient)

Usage:
curl -X POST http://localhost:8000/api/v1/analyze-upload \ -F "cv_file=@cv.pdf" \ -F "position_framework={\role_title:\Engineer}" \ -F "company_criteria={\company_name:\ACME}" \ -F "llm_provider=auto"