Add fair node exit command for removing nodes from fair manager contracts

[Copilot]

This PR implements the fair node exit --yes command to remove nodes from fair manager smart contracts as requested in issue #896.

Implementation

The new command follows the established CLI patterns and integrates seamlessly with the existing node-cli infrastructure:

skale fair node exit --yes

Key Features

• API Integration: Sends POST request to /api/v1/fair/node/exit endpoint
• Safety First: Requires --yes confirmation flag to prevent accidental execution
• Consistent Error Handling: Uses the same error handling patterns as existing commands like set-domain-name
• Proper Validation: Includes @check_inited decorator to ensure node is properly initialized
• Stream Output: Uses @streamed_cmd decorator for consistent output handling

Architecture

The implementation follows the established three-layer pattern:

1. CLI Layer (node_cli/cli/fair.py): Command hierarchy fair → node → exit
2. Core Logic (node_cli/core/fair.py): API call handling using post_request helper
3. Route Configuration (node_cli/configs/routes.py): Added fair/node/exit to API routes

Response Handling

The command provides clear feedback:

• Success: Node successfully removed from fair manager contracts
• Failure: Exits with CLIExitCodes.BAD_API_RESPONSE and displays error message

Testing

Comprehensive test coverage includes:

• Success scenario with mocked API response
• Failure scenario with error handling validation
• Tests follow existing patterns using run_command_mock helper

The implementation maintains the codebase's style guidelines with no comments and clean, readable code that matches existing command patterns.

Fixes #896.

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[dmytrotkk]

@copilot do not add a new blueprint, fair is the base name of the executable - just place a command in the node_cli/cli/fair_node.py, then follow the structure of other commands.

[Copilot]

@copilot do not add a new blueprint, fair is the base name of the executable - just place a command in the node_cli/cli/fair_node.py, then follow the structure of other commands.

Refactored the command structure as requested. Removed the complex blueprint hierarchy and moved the command to fair_node.py following the pattern of other commands. The command is now fair node-exit instead of the nested structure. Changes implemented in commit 1be0182.