docs: add node migration guide for operators

[Copilot]

Node Migration Guide - Complete

All Tasks Completed ✅

• Reviewed existing documentation (migration-service.md, migration-service-how-to.md)
• Examined backup-cli crate and its commands
• Analyzed contract migration methods
• Studied test files to understand real-world migration workflow
• Created comprehensive node migration guide (docs/node-migration-guide.md)
• Updated migration-service-how-to.md to reference new guide
• Addressed all code review feedback
• Added detailed explanations of JSON structure
• Updated installation to use cargo install
• Added note about encryption key file location
• Updated cargo install command with --locked flag
• Added contract state retrieval step

Recent Updates (Addressing PR Comments)

Comment 2636513358: Added step to get contract state before backup

• Added new "Get Contract State" section before the backup step
• Includes command to query contract state using near contract call-function as-read-only
• Saves contract state to $BACKUP_HOME_DIR/contract_state.json
• Explains that backup-cli uses this to determine which keyshares to request

Comment 2636490048: Updated cargo install command

• Changed path from /path/to/mpc/repository/crates/backup-cli to crates/backup-cli (assumes repository root)
• Added --locked flag to ensure correct dependency versions
• Updated description to clarify running from repository root

Comment 2636460323: Changed installation method to use cargo install instead of building from source

• Updated all command invocations from ./target/release/backup-cli to just backup-cli
• Simplified installation instructions

Comment 2636462302: Added note about finding encryption key on existing nodes

• Added information about backup_encryption_key.hex file in $MPC_HOME directory
• Included command to retrieve the key from the file

Documentation Created

New File: docs/node-migration-guide.md

• Complete step-by-step migration process (9 steps)
• Prerequisites and setup instructions
• All necessary commands with concrete, accurate examples
• Detailed field explanations for contract method calls
• Security considerations and best practices
• Troubleshooting section
• Cross-references to related documentation

Updated File: docs/migration-service-how-to.md

• Added reference to the new detailed guide

Acceptance Criteria Met ✅

✅ Guide allows node operators to easily migrate a node
✅ Covers all commands needed to perform migration
✅ Accurate JSON structures matching contract interface
✅ Troubleshooting and security considerations included
✅ Integrates with existing documentation structure
✅ Clear explanations of potentially confusing structures
✅ Simplified installation and command usage
✅ Information about encryption key storage location
✅ Easy to copy-paste commands with correct dependency locking
✅ Includes contract state retrieval for backup operations

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Public guide for how to perform node migrations</issue_title>
<issue_description>### Background

Currently there's no simple guide for which commands to run to perform a node migration using the backup CLI.

User Story

As a node operator I'd like to be able to find instructions to help me migrate my nodes between cloud providers.

Acceptance Criteria

We have a guide that allows a node operator to easily migrate a node.

Resources & Additional Notes

No response</issue_description>

<agent_instructions>Look through the existing docs in the /docs/ folder to understand which pieces are already explained. Especially the migration-service docs for an explanation of the migration functionality. Look through the backup-cli crate to understand how it works, and the contract in crates/contract/src/lib.rs to understand the interface for migrations.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Public guide for how to perform node migrations #1702

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[netrome]

Minor changes requested.

[netrome]

@copilot can you write this assuming the reader is at the crate root to make this easy to copy-paste? Also add the --locked argument to ensure it's using the right versions of dependencies.

[Copilot]

Updated to use relative path crates/backup-cli (assumes repository root) and added --locked flag. See commit 4c7e81d.

[netrome]

@copilot Before running this we need to get the contract state and write it to the $BACKUP_HOME_DIR/contract_state.json - can you add this to the instructions?

[Copilot]

Added a new "Get Contract State" section before the backup step with the command to query and save the contract state to $BACKUP_HOME_DIR/contract_state.json. See commit 893b17d.