capitalize error message

Let's not assume, nor force, that the backend provides error messages
in a format that we want to present. Hence we capitalize ourselves
for consistency.

app/src/lib/backend/ipc.ts

@@ -22,10 +22,17 @@ export class UserError extends Error {
 		const cause = error instanceof Error ? error : undefined;
 		const code = error.code ?? Code.Unknown;
 		const message = error.message ?? error;
-		return new UserError(message, code, cause);
+		return new UserError(capitalize(message), code, cause);
 	}
 }
 
+function capitalize(str: string): string {
+	if (str.length === 0) {
+		return str;
+	}
+	return str.charAt(0).toUpperCase() + str.slice(1);
+}
+
 export async function invoke<T>(command: string, params: Record<string, unknown> = {}): Promise<T> {
 	// This commented out code can be used to delay/reject an api call
 	// return new Promise<T>((resolve, reject) => {