Refactor: consolidate test helpers, parameterize tests, and fix WASM OOM bug

Cargo.toml

@@ -74,5 +74,6 @@ aws-smithy-types = "1"
 bytes = "1"
 http = "1"
 rustls = { version = "0.23", features = ["ring"] }
+rstest = "0.25"
 serial_test = "3"
 tempfile = "3"

src/adapters/server/auth.rs

@@ -277,11 +277,12 @@ pub(super) fn parse_query_params(
     for (name, value) in url::form_urlencoded::parse(query.as_bytes()) {
         let name = name.into_owned();
         let value = value.into_owned();
-        if params.insert(name.clone(), value).is_some() {
+        if params.contains_key(&name) {
             return Err(bad_request_response(&format!(
                 "query parameter `{name}` must not be repeated"
             )));
         }
+        params.insert(name, value);
     }
 
     Ok(params)

src/adapters/wasm.rs

@@ -94,7 +94,12 @@ pub struct WasmInspectResponse {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct WasmTransformResponse {
-    /// Transformed output bytes. JavaScript receives this as a `Uint8Array`.
+    /// Transformed output bytes.
+    ///
+    /// Skipped during JSON serialization because the bytes are passed separately
+    /// through the [`WasmTransformResponse`] getter to avoid duplicating potentially
+    /// megabytes of image data inside the JSON metadata string.
+    #[serde(skip_serializing)]
     pub bytes: Vec<u8>,
     /// Metadata describing the transformed artifact.
     pub artifact: WasmArtifactInfo,