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-agent/src/wal.rs

@@ -786,7 +786,7 @@ mod tests {
         let dir = TempDir::new().unwrap();
         let wal_path = dir.path().join("test.h5.wal");
         let unicode_chunk = "Hello 世界! 🌍 émojis & ünïcödé";
-        let embedding = vec![0.1, -0.2, 3.14159, f32::MAX, f32::MIN_POSITIVE];
+        let embedding = vec![0.1, -0.2, 3.4567, f32::MAX, f32::MIN_POSITIVE];
         {
             let mut wal = WalFile::open(&wal_path).unwrap();
             let entry = WalEntry {