Prevent unused imports for engine debug output

In the process, switch from the `web-sys` crate's `console::log_1`
function to Sycamore's more flexible `console_log` macro. The latter
works both inside and outside the browser, so we can use it without
checking whether we're compiling to WebAssembly.

app-proto/src/engine.rs

@@ -1,7 +1,10 @@
 use lazy_static::lazy_static;
 use nalgebra::{Const, DMatrix, DVector, DVectorView, Dyn, SymmetricEigen};
 use std::fmt::{Display, Error, Formatter};
-use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
+
+/* DEBUG */
+#[cfg(not(feature = "dev"))]
+use sycamore::prelude::console_log;
 
 // --- elements ---
 
@@ -167,10 +170,8 @@ impl ConfigSubspace {
         
         /* DEBUG */
         // print the eigenvalues
-        #[cfg(all(target_family = "wasm", target_os = "unknown"))]
-        console::log_1(&JsValue::from(
-            format!("Eigenvalues used to find kernel:{}", eig.eigenvalues)
-        ));
+        #[cfg(not(feature = "dev"))]
+        console_log!("Eigenvalues used to find kernel:{}", eig.eigenvalues);
         
         // express the basis in the standard coordinates
         let basis_std = proj_to_std * &basis_proj;