fix(core,android,app): say why a crawl failed, not only which URL

A transport failure's text is reqwest's "error sending request for url
(…)", and the cause sits further down its source chain. Error::describe
appends the causes and drops the URL, so the reason fits on a share row.

crates/pstr-android/src/lib.rs

@@ -2637,11 +2637,11 @@ impl AndroidEngine {
                     if let Err(error) = self
                         .catalog
                         .lock()
-                        .record_crawl_failure(&id, &error.to_string())
+                        .record_crawl_failure(&id, &error.describe())
                     {
                         log::warn!("record a failed crawl: {error}");
                     }
-                    return Err(BridgeError::from_display(error));
+                    return Err(BridgeError::from_display(error.describe()));
                 }
             };
             let rows = build_rows(&id, &nodes);