clawhdf5-remote: clippy clean with every feature set

checked_div in the test server's throttle, a slice for the single range
of fetch_first, and dead-code allowances for the redaction helpers in a
build with neither http nor a cloud store.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

crates/clawhdf5-remote/src/error.rs

@@ -66,12 +66,20 @@ pub fn redact_url(url: &str) -> String {
 /// Replaces the secret parts of one URL (its userinfo and query string,
 /// and the URL itself) wherever they appear in a message — such as the
 /// text of an error from the HTTP client.
+#[cfg_attr(
+    not(any(feature = "http", feature = "s3", feature = "gcs", feature = "azure")),
+    allow(dead_code)
+)]
 #[derive(Debug, Clone)]
 pub(crate) struct Redactor {
     shown: String,
     secrets: Vec<(String, String)>,
 }
 
+#[cfg_attr(
+    not(any(feature = "http", feature = "s3", feature = "gcs", feature = "azure")),
+    allow(dead_code)
+)]
 impl Redactor {
     pub(crate) fn new(url: &str) -> Redactor {
         let shown = redact_url(url);
@@ -177,7 +185,10 @@ pub enum RemoteError {
 
 impl RemoteError {
     /// The error with every secret part of `r`'s URL scrubbed from its text.
-    #[cfg_attr(not(any(feature = "http", feature = "object-store")), allow(dead_code))]
+    #[cfg_attr(
+        not(any(feature = "http", feature = "s3", feature = "gcs", feature = "azure")),
+        allow(dead_code)
+    )]
     pub(crate) fn scrubbed(self, r: &Redactor) -> RemoteError {
         let f = |s: String| r.scrub(&s);
         match self {