Use multi-line textarea for complex widget config fields

The Grafana chart widget's 'query' field (PromQL) and any schema field
marked format:'textarea' now render as a resizable 4-row Textarea with
monospace font, instead of a single-line Input. Makes complex queries
much easier to read and edit.

The field-renderer heuristic: key === 'query' or schema format ===
'textarea' → Textarea; everything else stays an Input (numbers stay
number inputs). 127 tests pass; lint/build green.

frontend/src/components/WidgetConfigDialog.tsx

@@ -7,6 +7,7 @@ import {
 } from "@/components/ui/dialog";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
+import { Textarea } from "@/components/ui/textarea";
 import { Label } from "@/components/ui/label";
 import { Switch } from "@/components/ui/switch";
 import {
@@ -133,17 +134,35 @@ function WidgetConfigEditor({
 
 	return (
 		<div className="flex flex-col gap-3">
-			{properties.map(([key, schema]) => {
+		{properties.map(([key, schema]) => {
 				const isNumber =
 					(schema as { type?: string }).type === "integer" ||
 					(schema as { type?: string }).type === "number";
+				// Use a multi-line textarea for fields that tend to hold complex
+				// multi-line values (PromQL, text blocks, etc.). The widget kind's
+				// config schema can opt in via `format: "textarea"`; the well-known
+				// `query` field is treated as textarea by default.
+				const schemaFormat = (schema as { format?: string }).format;
+				const isTextarea =
+					schemaFormat === "textarea" || key === "query";
 				return (
-					<Field
-						key={key}
-						label={key}
-						htmlFor={`widget-cfg-${key}`}
-						helper={(schema as { description?: string }).description}
-					>
+				<Field
+					key={key}
+					label={key}
+					htmlFor={`widget-cfg-${key}`}
+					helper={(schema as { description?: string }).description}
+				>
+					{isTextarea ? (
+						<Textarea
+							id={`widget-cfg-${key}`}
+							rows={4}
+							className="resize-y font-mono text-xs"
+							value={String(config[key] ?? "")}
+							onChange={(e) =>
+								onChange({ ...config, [key]: e.target.value })
+							}
+						/>
+					) : (
 						<Input
 							id={`widget-cfg-${key}`}
 							type={isNumber ? "number" : "text"}
@@ -159,7 +178,8 @@ function WidgetConfigEditor({
 								})
 							}
 						/>
-					</Field>
+					)}
+				</Field>
 				);
 			})}
 		</div>
@@ -334,10 +354,18 @@ export function WidgetConfigDialog({ open, onClose, serviceId }: Props) {
 			/>
 			{!isMobile ? (
 				<div className="flex justify-end gap-2">
-					<Button variant="outline" onClick={reset} className="mobile-touch-target">
+					<Button
+						variant="outline"
+						onClick={reset}
+						className="mobile-touch-target"
+					>
 						Back
 					</Button>
-					<Button onClick={saveDraft} disabled={saveWidget.isPending} className="mobile-touch-target">
+					<Button
+						onClick={saveDraft}
+						disabled={saveWidget.isPending}
+						className="mobile-touch-target"
+					>
 						Save widget
 					</Button>
 				</div>