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-format/src/link_message.rs

@@ -413,11 +413,8 @@ mod tests {
     #[test]
     fn soft_link() {
         let target = "/group1/dataset";
-        let mut data = Vec::new();
-        data.push(1); // version
-        data.push(0x08); // flags: bit 3 = link type present, name size = 1 byte (bits 0-1 = 0)
-        data.push(1); // link type = soft
-        data.push(4); // name length = 4
+        // version, flags (bit 3 = link type present, name size = 1 byte), link type = soft, name length = 4
+        let mut data = vec![1, 0x08, 1, 4];
         data.extend_from_slice(b"link");
         data.extend_from_slice(&(target.len() as u16).to_le_bytes());
         data.extend_from_slice(target.as_bytes());
@@ -455,12 +452,8 @@ mod tests {
 
     #[test]
     fn invalid_link_type() {
-        let mut data = Vec::new();
-        data.push(1); // version
-        data.push(0x08); // flags: bit 3 = link type present
-        data.push(99); // invalid link type
-        data.push(1); // name length = 1
-        data.push(b'x');
+        // version, flags (bit 3 = link type present), invalid link type = 99, name length = 1, name = 'x'
+        let data = vec![1, 0x08, 99, 1, b'x'];
         let err = LinkMessage::parse(&data, 8).unwrap_err();
         assert_eq!(err, FormatError::InvalidLinkType(99));
     }