fix: improve error messages and placeholder naming per review feedback

Agent-Logs-Url: https://github.com/objectstack-ai/objectui/sessions/c72f47f2-b9dd-4364-b613-535fb3b9d405

Co-authored-by: xuyushun441-sys <255036401+xuyushun441-sys@users.noreply.github.com>

Author: Copilot

apps/console/src/config/metadataTypeRegistry.ts

@@ -175,7 +175,7 @@ export const METADATA_TYPES: MetadataTypeConfig[] = [
       { key: 'description', label: 'Description' },
     ],
     formFields: [
-      { key: 'name', label: 'Name', required: true, placeholder: 'my_dashboard', disabledOnEdit: true },
+      { key: 'name', label: 'Name', required: true, placeholder: 'dashboard_name', disabledOnEdit: true },
       { key: 'label', label: 'Label', required: true, placeholder: 'My Dashboard' },
       { key: 'description', label: 'Description', type: 'textarea', placeholder: 'Brief description' },
     ],
@@ -192,7 +192,7 @@ export const METADATA_TYPES: MetadataTypeConfig[] = [
       { key: 'description', label: 'Description' },
     ],
     formFields: [
-      { key: 'name', label: 'Name', required: true, placeholder: 'my_page', disabledOnEdit: true },
+      { key: 'name', label: 'Name', required: true, placeholder: 'page_name', disabledOnEdit: true },
       { key: 'label', label: 'Label', required: true, placeholder: 'My Page' },
       { key: 'description', label: 'Description', type: 'textarea', placeholder: 'Brief description' },
     ],
@@ -209,7 +209,7 @@ export const METADATA_TYPES: MetadataTypeConfig[] = [
       { key: 'description', label: 'Description' },
     ],
     formFields: [
-      { key: 'name', label: 'Name', required: true, placeholder: 'my_report', disabledOnEdit: true },
+      { key: 'name', label: 'Name', required: true, placeholder: 'report_name', disabledOnEdit: true },
       { key: 'label', label: 'Label', required: true, placeholder: 'My Report' },
       { key: 'description', label: 'Description', type: 'textarea', placeholder: 'Brief description' },
     ],

apps/console/src/pages/system/MetadataDetailPage.tsx

@@ -110,7 +110,7 @@ export function MetadataDetailPage() {
         toast.success(`${config?.label ?? 'Item'} "${itemName}" updated`);
       } catch {
         toast.error(`Failed to update "${itemName}"`);
-        throw new Error('save failed');
+        throw new Error(`Failed to save ${config?.label ?? 'item'} "${itemName}"`);
       } finally {
         setSaving(false);
       }

apps/console/src/pages/system/MetadataManagerPage.tsx

@@ -174,7 +174,7 @@ export function MetadataManagerPage() {
           ? `Failed to update "${name}"`
           : `Failed to create "${name}"`,
       );
-      throw new Error('save failed');
+      throw new Error(`Failed to save ${config?.label ?? 'item'} "${name}"`);
     } finally {
       setSaving(false);
     }