Fix sidecar.log not created: ensure data dir exists

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src-tauri/src/sidecar/mod.rs

@@ -236,13 +236,18 @@ impl SidecarManager {
 
         // Log sidecar stderr to a file for diagnostics
         let stderr_cfg = if let Some(data_dir) = DATA_DIR.get() {
+            let _ = std::fs::create_dir_all(data_dir);
             let log_path = data_dir.join("sidecar.log");
             eprintln!("[sidecar-rs] Sidecar stderr → {}", log_path.display());
             match std::fs::File::create(&log_path) {
                 Ok(f) => Stdio::from(f),
-                Err(_) => Stdio::inherit(),
+                Err(e) => {
+                    eprintln!("[sidecar-rs] Failed to create sidecar.log: {e}");
+                    Stdio::inherit()
+                }
             }
         } else {
+            eprintln!("[sidecar-rs] DATA_DIR not set, sidecar stderr will not be logged");
             Stdio::inherit()
         };