geometry: partition cuts and the projection mesher report progress and stop when cancelled

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

crates/geometry/src/lib.rs

@@ -46,6 +46,9 @@ pub enum Error {
     Invalid(String),
     #[error("the geometry operation failed: {0}")]
     Failed(String),
+    /// From the model layer: a cancelled job ([`fieldcraft_model::progress::check`]).
+    #[error(transparent)]
+    Model(#[from] fieldcraft_model::Error),
 }
 
 pub type Result<T> = std::result::Result<T, Error>;