feat: complete translation language controls and styling

Tests/ConjureKitTests/MyMemoryTests.swift

@@ -38,6 +38,19 @@ import Testing
     #expect(translation == "こんにちは")
 }
 
+@Test func myMemoryRequestsReversePairAndOnlyUsesMatchingFallback() async throws {
+    let body = #"{"responseStatus":200,"responseData":{"translatedText":""},"matches":[{"segment":"おはよう","translation":"間違い","source":"en","target":"ja"},{"segment":"おはよう","translation":"bonjour","source":"ja","target":"fr"},{"segment":"おはようございます","translation":"Good morning!","source":"ja","target":"en"},{"segment":"おはよう","translation":"Good morning","source":"ja-JP","target":"en-GB"}]}"#
+    let translation = try await MyMemoryAPI.translate(
+        "おはよう", sourceLanguage: "ja", targetLanguage: "en"
+    ) { request in
+        let items = try #require(URLComponents(url: request.url!, resolvingAgainstBaseURL: false)?.queryItems)
+        #expect(items.contains(URLQueryItem(name: "q", value: "おはよう")))
+        #expect(items.contains(URLQueryItem(name: "langpair", value: "ja|en")))
+        return (Data(body.utf8), HTTPURLResponse(url: request.url!, statusCode: 200, httpVersion: nil, headerFields: nil)!)
+    }
+    #expect(translation == "Good morning")
+}
+
 @Test func myMemoryNeverUsesMatchesToBypassFailureOrReplacePrimaryTranslation() async throws {
     let matches = #""matches":[{"segment":"hello","translation":"こんにちは","source":"en","target":"ja"}]"#
     for metadata in [#""responseStatus":403"#, #""responseStatus":200,"quotaFinished":true"#] {