Function read_pin 

pub fn read_pin(
    package: &str,
    toolsets_root: &Path,
) -> Result<Option<ToolsetPinRecord>, ToolsetInstallError>

Re-export stellar_agent_toolsets_install::read_pin as a crate-level convenience so MCP/CLI consumers can read pins without adding a direct dep on stellar-agent-toolsets-install. Reads and parses the pin record for package from toolsets_root.

Validates package against the [a-z0-9-] charset BEFORE constructing any filesystem path: a package value containing /, \, ., .., or any character outside [a-z0-9-] is rejected immediately with ToolsetInstallError::InvalidPackageName and produces NO filesystem path join.

Returns None if the pin file does not exist (toolset not installed).

Errors

• ToolsetInstallError::InvalidPackageName — package fails the [a-z0-9-] charset validation.
• ToolsetInstallError::PinRecordMalformed — pin file exists but cannot be parsed or contains an invalid package name.
• ToolsetInstallError::Io — unexpected I/O error (not NotFound).