fix: surface hidden errors and add batch rejection tests

Fix empty catch blocks in settings dialog (logo upload/delete) and
automate page (pipeline save) that silently swallowed errors. Users
now see error messages when these operations fail.

Add 5 integration tests verifying batch endpoint returns 404 for
custom-route tools (remove-background, upscale, ocr, blur-faces,
erase-object), matching the pipeline rejection tests.

apps/web/src/components/settings/settings-dialog.tsx

@@ -295,7 +295,7 @@ function SystemSection() {
       });
       setSettings((prev) => ({ ...prev, customLogo: "true" }));
     } catch {
-      /* handle error */
+      setSaveMsg("Failed to upload logo.");
     }
   };
 
@@ -304,7 +304,7 @@ function SystemSection() {
       await apiDelete("/v1/settings/logo");
       setSettings((prev) => ({ ...prev, customLogo: "false" }));
     } catch {
-      /* handle error */
+      setSaveMsg("Failed to delete logo.");
     }
   };