resolve_install_hint(
package: str,
distribution_name: str = 'deepagents-code'
) -> InstallHintResolve how to recover from a missing provider package.
Centralizes the extra_for_package -> install_package_command fallback so
the TUI startup hint and the model-initialization error path render
consistent recovery data without each re-implementing the branching and
error handling. Prefers the installable extra; otherwise derives a raw
package install command, degrading to a manual hint (both fields None)
when that cannot be determined.
Callers own sentence wording and command framing (for example interactive
/install / /model copy). This helper only resolves the recovery action.