Add Input Validation to CLI Commands Based on Server Request Models

[virajbhartiya]

Summary

This PR adds comprehensive input validation to all CLI commands in the parity-client, ensuring that user inputs match the expected request body structures from the parity-server API.

Changes Made

New Validation Utilities (internal/utils/validation.go)

• Ethereum Address Validation: Validates format and checksum
• Private Key Validation: Validates hex format and length
• Amount Validation: Ensures positive values with minimum thresholds
• URL Validation: Validates HTTP/HTTPS URLs
• Device ID Validation: Ensures proper length and format
• Task Parameter Validation: Title, description, Docker image, reward validation
• LLM Parameter Validation: Model names, prompts, max tokens validation
• Federated Learning Validation: Session names, rounds, participants, dataset CIDs
• Storage Validation: File paths, CIDs, output paths

Enhanced CLI Commands

• Auth Command: Validates private key format and length
• Stake Command: Validates stake amount with minimum threshold
• LLM Commands: Validates model names and prompts
• Federated Learning Commands: Validates session parameters, learning rates, batch sizes
• Storage Commands: Validates file paths and CIDs
• Reputation Commands: Validates device IDs and runner parameters

Error Handling

• Custom ValidationError type with field-specific error messages
• Descriptive error messages that guide users to correct input
• Consistent error format across all commands

Benefits

1. Improved User Experience: Clear error messages help users understand what went wrong
2. API Consistency: CLI inputs now match server-side validation requirements
3. Reduced Server Errors: Invalid requests are caught client-side before reaching the server
4. Better Security: Input validation prevents malformed data from being processed
5. Maintainability: Centralized validation logic makes it easy to update validation rules