Add PHPResponse.forHttpCode() shorthand (#1322)

Short and sweet – adds a `PHPResponse.forHttpCode()` method to
streamline the creation of various OK and error response objects.

For example:

```ts
// Before
const error500 = new PHPResponse(500, {}, new TextEncoder().encode("Internal Server Error"))

// After
const error500 = PHPResponse.forHttpCode(500);
```

 ## Testing instructions

None, this PR only adds new code without using it just yet.

packages/php-wasm/universal/src/lib/php-response.ts

@@ -31,6 +31,22 @@ export interface PHPResponseData {
 	readonly httpStatusCode: number;
 }
 
+const responseTexts: Record<number, string> = {
+	500: 'Internal Server Error',
+	502: 'Bad Gateway',
+	404: 'Not Found',
+	403: 'Forbidden',
+	401: 'Unauthorized',
+	400: 'Bad Request',
+	301: 'Moved Permanently',
+	302: 'Found',
+	307: 'Temporary Redirect',
+	308: 'Permanent Redirect',
+	204: 'No Content',
+	201: 'Created',
+	200: 'OK',
+};
+
 /**
  * PHP response. Body is an `ArrayBuffer` because it can
  * contain binary data.
@@ -68,6 +84,16 @@ export class PHPResponse implements PHPResponseData {
 		this.errors = errors;
 	}
 
+	static forHttpCode(httpStatusCode: number, text = '') {
+		return new PHPResponse(
+			httpStatusCode,
+			{},
+			new TextEncoder().encode(
+				text || responseTexts[httpStatusCode] || ''
+			)
+		);
+	}
+
 	static fromRawData(data: PHPResponseData): PHPResponse {
 		return new PHPResponse(
 			data.httpStatusCode,