Add descriptive error messages across all API routes and toast notifications on client pages

- 86 catch blocks in 49 API route files now return the actual error message via error.message
- 14 campaign/lead/config catch blocks that lacked console.error now log errors
- 17 client pages/components now show toast.error notifications on API failures
- Silent .catch(() => {}) and finally-only try blocks now surface errors to users

src/app/api/custom-fields/route.ts

@@ -25,7 +25,8 @@ export async function GET(request: NextRequest) {
     return NextResponse.json(result.rows)
   } catch (error) {
     console.error("Custom fields API error:", error)
-    return NextResponse.json({ error: "Failed to load custom fields" }, { status: 500 })
+    const message = error instanceof Error ? error.message : "Failed to load custom fields"
+    return NextResponse.json({ error: message }, { status: 500 })
   }
 }
 
@@ -62,7 +63,8 @@ export async function POST(request: NextRequest) {
       return NextResponse.json({ error: "A field with this key already exists for this entity" }, { status: 409 })
     }
     console.error("Custom fields POST error:", error)
-    return NextResponse.json({ error: "Failed to create custom field" }, { status: 500 })
+    const message = error instanceof Error ? error.message : "Failed to create custom field"
+    return NextResponse.json({ error: message }, { status: 500 })
   }
 }
 
@@ -106,7 +108,8 @@ export async function PATCH(request: NextRequest) {
     return NextResponse.json({ success: true })
   } catch (error) {
     console.error("Custom fields PATCH error:", error)
-    return NextResponse.json({ error: "Failed to update custom field" }, { status: 500 })
+    const message = error instanceof Error ? error.message : "Failed to update custom field"
+    return NextResponse.json({ error: message }, { status: 500 })
   }
 }
 
@@ -120,6 +123,7 @@ export async function DELETE(request: NextRequest) {
     return NextResponse.json({ success: true })
   } catch (error) {
     console.error("Custom fields DELETE error:", error)
-    return NextResponse.json({ error: "Failed to delete custom field" }, { status: 500 })
+    const message = error instanceof Error ? error.message : "Failed to delete custom field"
+    return NextResponse.json({ error: message }, { status: 500 })
   }
 }