refactor(ribbon): simplify draw tool registry

build.rs

@@ -4,7 +4,6 @@
 use std::path::Path;
 
 fn main() {
-    generate_draw_panel_tools();
     let version = std::env::var("CARGO_PKG_VERSION").expect("Cargo package version");
     let parts: Vec<&str> = version.split('.').collect();
     let app_version = if parts.len() == 3 && parts[0].len() == 4
@@ -82,27 +81,3 @@ fn main() {
         }
     }
 }
-
-/// Each drawing button can contribute its own expression without editing a registry.
-fn generate_draw_panel_tools() {
-    let manifest = std::path::PathBuf::from(std::env::var_os("CARGO_MANIFEST_DIR").expect("Cargo manifest directory"));
-    let directory = manifest.join("src/ui/ribbon/draw_tools");
-    println!("cargo:rerun-if-changed={}", directory.display());
-    let mut files = match std::fs::read_dir(&directory) {
-        Ok(entries) => entries.map(|entry| entry.expect("Draw tool directory entry").path())
-            .filter(|path| path.is_file() && path.extension().is_some_and(|extension| extension == "rs"))
-            .collect::<Vec<_>>(),
-        Err(error) if error.kind() == std::io::ErrorKind::NotFound => Vec::new(),
-        Err(error) => panic!("Cannot read Draw tool contributions: {error}"),
-    };
-    files.sort_by(|left, right| left.file_name().cmp(&right.file_name()));
-    let mut source = String::from("const TOOLS: &[Tool] = &[\n");
-    for path in files {
-        println!("cargo:rerun-if-changed={}", path.display());
-        // Debug string formatting produces a quoted Rust literal, including Windows escapes.
-        source.push_str(&format!("    include!({:?}),\n", path.to_str().expect("UTF-8 Draw tool path")));
-    }
-    source.push_str("];\n");
-    let output = std::path::PathBuf::from(std::env::var_os("OUT_DIR").expect("Cargo output directory"));
-    std::fs::write(output.join("draw_panel_tools.rs"), source).expect("Write Draw tool registry");
-}