Enforce min_diecut_version or remove the field

[raiderrobert]

Context

In src/config/schema.rs (line 29):

pub min_diecut_version: Option<String>,

This field is parsed from diecut.toml but never checked during template resolution. If a template specifies a minimum version that the current binary doesn't satisfy, it will silently proceed, potentially producing incorrect output.

Suggestion

Either:

1. Enforce the check during validate() or plan_generation by comparing against the crate version (env!("CARGO_PKG_VERSION"))
2. Remove the field if it's not going to be enforced, to avoid misleading template authors