Implement get-address tool

[juntao]

Summary

• Implement get-address CLI tool to read public Ethereum address from wallet keystore
• No password required - reads only the unencrypted address field
• Support custom wallet path via --wallet/-w flag
• Support custom config path via --config/-c flag
• Return proper exit codes (12 for wallet not found)
• Add comprehensive README documentation

Test plan

• Build succeeds: cargo build --release -p get-address
• All tests pass: cargo test --all
• Clippy passes: cargo clippy --all -- -D warnings
• Format check passes: cargo fmt --all -- --check
• --help shows usage information
• Returns correct address when given valid wallet
• Returns exit code 12 when wallet not found

Generated with Claude Code

[Copilot]

Pull request overview

This PR implements a new CLI tool get-address that retrieves the public Ethereum address from an x402 wallet keystore file without requiring password decryption.

Changes:

• Added new get-address CLI tool with support for custom wallet and config paths
• Implemented proper exit code handling (exit code 12 for wallet not found, exit code 1 for other errors)
• Added comprehensive README documentation covering usage, security considerations, and exit codes

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
get-address/src/main.rs	Implements the CLI tool with argument parsing, config loading, and wallet address retrieval with proper exit code handling
get-address/Cargo.toml	Adds dependencies for clap (CLI parsing), x402_common (wallet/config functionality), and anyhow
get-address/README.md	Provides comprehensive documentation including usage examples, security notes, and exit codes

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[Copilot]

The anyhow dependency is declared but never used in the code. The main.rs file uses std::process::ExitCode for error handling instead of anyhow's Result type. Consider removing this unused dependency.

Suggested change

anyhow = "1"

[Copilot]

When loading configuration fails, the error is silently ignored. If a user explicitly specifies a config path via --config that contains invalid TOML or has IO errors, they won't be notified of the problem. Consider checking if args.config.is_some() and if so, propagate the error to inform the user about the invalid config file they explicitly specified.

Suggested change

	let wallet_path = if let Some(path) = args.wallet {
	Some(path)
	} else {
	// Try to load config for default wallet path
	match Config::load_from(args.config.as_deref()) {
	Ok(config) => Some(config.wallet_path()),
	Err(_) => None, // Use library default
	let config_path = args.config.as_deref();
	let wallet_path = if let Some(path) = args.wallet.clone() {
	Some(path)
	} else {
	// Try to load config for default wallet path
	match Config::load_from(config_path) {
	Ok(config) => Some(config.wallet_path()),
	Err(e) => {
	// If the user explicitly specified a config path, surface the error
	if let Some(path) = config_path {
	eprintln!(
	"Error loading config file '{}': {}",
	path.display(),
	e
	);
	return ExitCode::FAILURE;
	}
	// No explicit config provided: fall back to library default
	None
	}