feat(wasm): clawhdf5-wasm, the reader for JavaScript via wasm-bindgen

open(bytes) -> H5File with kind/list/info/attrs/attrErrors/read/
readHyperslab. Numeric data comes back in the typed array of the
stored width (Int16Array for i16, BigInt64Array for i64, Float32Array
for f32/f16, ...), strings and enum names as string arrays, array
datatypes flattened with their dims appended to the shape. Compound,
reference, opaque and VL-sequence datasets are refused with an error
naming the type; nothing is returned as reinterpreted bytes.

The logic is in a plain-Rust core module, tested natively: unit tests,
and h5py_interop, which compares every dataset, hyperslab, listing and
attribute of an h5py- and a netCDF4-written file with what libhdf5
reads back (generator shared with the Node test of the built package).

No mmap, no threads; lz4 is on, zstd/szip (C) are not. A
wasm-release profile (opt-level s, LTO) serves the browser build.
ci-test.sh lints the crate for wasm32 and checks it builds no C.

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

README.md

@@ -587,7 +587,7 @@ let exported = backend.export_markdown("MEMORY.md")?;
 ## Crate Map
 
 ```
-clawhdf5 workspace (16 crates, ~86K lines of Rust in src/, ~104K with tests
+clawhdf5 workspace (17 crates, ~86K lines of Rust in src/, ~104K with tests
                      and benches; plus libaec-sys, an internal FFI bindings
                      crate for the optional szip feature)
 │
@@ -610,7 +610,8 @@ clawhdf5 workspace (16 crates, ~86K lines of Rust in src/, ~104K with tests
 │
 ├── Bindings
 │   ├── clawhdf5-py          — Python (PyO3)
-│   └── clawhdf5-napi        — Node.js (napi-rs)
+│   ├── clawhdf5-napi        — Node.js (napi-rs)
+│   └── clawhdf5-wasm        — Browser (WebAssembly, wasm-bindgen; read-only)
 │
 └── Tooling
     └── clawhdf5-bench       — Benchmark suite