refactor(operation,link): port __toString to Display

Move __toString ports to std::fmt::Display: convert Link's inherent
to_string() and make OperationInterface require Display instead of a
to_string() method, with each operation implementing Display.

Also fix the operation __toString output to use show(false), matching
SolverOperation::__toString() (was show(true)).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/crates/shirabe/src/dependency_resolver/operation/install_operation.rs b/crates/shirabe/src/dependency_resolver/operation/install_operation.rs
index 1331591..ca3286c 100644
--- a/crates/shirabe/src/dependency_resolver/operation/install_operation.rs
+++ b/crates/shirabe/src/dependency_resolver/operation/install_operation.rs
@@ -45,11 +45,13 @@ impl OperationInterface for InstallOperation {
         Self::format(self.package.clone(), lock)
     }
 
-    fn to_string(&self) -> String {
-        self.show(true)
-    }
-
     fn as_install_operation(&self) -> Option<&InstallOperation> {
         Some(self)
     }
 }
+
+impl std::fmt::Display for InstallOperation {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.show(false))
+    }
+}