ci: lint all targets, run interop suites for real, compile benches

- clippy --all-targets plus a clawhdf5-format feature matrix (parallel, lz4,
  zstd, pcodec, fast-checksum); fix the accumulated lint backlog in test,
  bench and feature-gated code (no behaviour changes).
- Install python3 + h5py/numpy/netCDF4/xarray in the CI container and set
  CLAWHDF5_REQUIRE_INTEROP=1, which makes a missing interop dependency a test
  failure. Every h5py/netCDF4 interop test used to skip silently in CI. Run
  the #[ignore]d writer_h5py_tests suite explicitly.
- cargo bench --no-run so benches can't rot; fix bench.rs and memory_bench.rs,
  which no longer compiled against the current strategy/consolidation APIs.
- Optional fuzz smoke run via CLAWHDF5_FUZZ_SECONDS.
- CHANGELOG and docs/known-issues.md updated.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

crates/clawhdf5/src/lib.rs

@@ -469,13 +469,10 @@ mod tests {
         let ds = file.dataset("data").unwrap();
 
         // Zero-copy should succeed for contiguous LE f64 on mmap
-        match ds.read_f64_zerocopy() {
-            Ok(slice) => {
-                assert_eq!(slice, &original[..]);
-                assert_eq!(slice, &ds.read_f64().unwrap()[..]);
-            }
-            Err(_) => {} // alignment issue, acceptable
-        }
+        if let Ok(slice) = ds.read_f64_zerocopy() {
+            assert_eq!(slice, &original[..]);
+            assert_eq!(slice, &ds.read_f64().unwrap()[..]);
+        } // else: alignment issue, acceptable
         assert_eq!(ds.read_f64().unwrap(), original);
 
         std::fs::remove_file(&path).ok();

crates/clawhdf5/tests/h5py_interop_tests.rs

@@ -10,6 +10,12 @@ use clawhdf5::{AttrValue, CompoundTypeBuilder, DType, File, FileBuilder};
 // Helpers
 // ---------------------------------------------------------------------------
 
+/// When `CLAWHDF5_REQUIRE_INTEROP=1` (set in CI), a missing Python dependency
+/// is a test failure instead of a silent skip.
+fn interop_required() -> bool {
+    std::env::var("CLAWHDF5_REQUIRE_INTEROP").is_ok_and(|v| v == "1")
+}
+
 fn python_available() -> bool {
     Command::new("python3")
         .args(["-c", "import h5py; print(h5py.__version__)"])
@@ -21,6 +27,10 @@ fn python_available() -> bool {
 macro_rules! skip_if_no_python {
     () => {
         if !python_available() {
+            assert!(
+                !interop_required(),
+                "CLAWHDF5_REQUIRE_INTEROP=1 but python3 with h5py is not available"
+            );
             eprintln!("SKIP: python3 with h5py not available");
             return;
         }

crates/clawhdf5/tests/integration_tests.rs

@@ -955,8 +955,10 @@ fn read_selection_all_matches_read_raw_on_chunked_dataset() {
     let via_read_f64 = ds.read_f64().unwrap();
     let via_selection_bytes = ds.read_selection(&Selection::All).unwrap();
     let via_selection: Vec<f64> = via_selection_bytes
-        .chunks_exact(8)
-        .map(|c| f64::from_le_bytes(c.try_into().unwrap()))
+        .as_chunks::<8>()
+        .0
+        .iter()
+        .map(|c| f64::from_le_bytes(*c))
         .collect();
 
     assert_eq!(via_read_f64, data);

crates/clawhdf5/tests/zerocopy_tests.rs

@@ -315,7 +315,7 @@ fn zerocopy_roundtrip_write_read() {
     let dir = std::env::temp_dir();
     let path = dir.join("zc_roundtrip.h5");
 
-    let original = vec![3.14, 2.718, 1.414, 1.732, 0.577];
+    let original = vec![3.25, 2.75, 1.414, 1.732, 0.577];
     let mut b = FileBuilder::new();
     b.create_dataset("data")
         .with_f64_data(&original)