Add Input Validation and Sanitization for All API Endpoints

[Abhay-2811]

Current Status

The API currently lacks input validation and sanitization, making it vulnerable to various attacks and potentially causing unexpected behavior. All endpoints accept user input without proper validation.

What's Needed

Implement comprehensive input validation and sanitization for:

Bucket Operations

• Bucket Names: Validate alphanumeric characters, length limits (1-63 chars), no special characters
• URL Parameters: Sanitize and validate all path parameters

File Operations

• File Names: Sanitize to prevent path traversal attacks, validate length and character set
• File Uploads: Validate file size limits, MIME types, and content
• Multipart Forms: Proper validation of form data

Implementation Requirements

• Create validation middleware for all endpoints
• Add input sanitization functions
• Implement file upload validation (size, type, content)
• Add URL parameter validation
• Create validation error responses
• Add unit tests for validation logic
• Update API documentation with validation rules

Security Considerations

• Prevent path traversal attacks
• Block malicious file uploads
• Validate all user inputs
• Add proper error messages without exposing internals

Files to Modify

• internal/handlers/ - Add validation to all handlers
• internal/middleware/ - Create new validation middleware
• test/ - Add validation test cases

[VeerChaurasia]

hey @Abhay-2811 is this issue open to work?