plugin: log build.rs bridge-file presence; use manifest dir for robust path

plugin/build.rs

@@ -26,8 +26,17 @@ fn main() {
     // Crane's deps-only build stubs out lib.rs and removes our bridge sources to
     // build a dummy crate that only compiles dependencies. Skip cxx-qt codegen in
     // that case - we just want cxx-qt-lib (the heavy dep) cached, not our own glue.
+    // Use CARGO_MANIFEST_DIR for a robust path that doesn't depend on cargo's CWD.
+    let manifest = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
     let bridge_files = ["src/system_stats.rs", "src/cpu_service.rs"];
-    if !bridge_files.iter().all(|p| std::path::Path::new(p).exists()) {
+    let present: Vec<bool> = bridge_files
+        .iter()
+        .map(|p| manifest.join(p).exists())
+        .collect();
+    println!("cargo:warning=build.rs manifest_dir={}", manifest.display());
+    println!("cargo:warning=build.rs bridge_files present: {present:?}");
+    if !present.iter().all(|b| *b) {
+        println!("cargo:warning=build.rs bailing: bridge files missing (deps-only build?)");
         return;
     }