CI / test (push) Failing after 4s
- Add ensure_len(data, offset, needed) helper to chunked_read.rs, data_read.rs, and local_heap.rs (matching the existing btree_v1.rs/ object_header.rs convention) and use it at every plain-arithmetic offset+size bounds check found in these files, closing usize-overflow panics reachable from crafted near-usize::MAX offsets/addresses. - collect_chunk_info: add a depth-limited internal wrapper (collect_chunk_info_inner, MAX_CHUNK_BTREE_DEPTH=64) to reject a crafted self-referencing/cyclic B-tree v1 chunk index instead of recursing unboundedly (stack-overflow DoS). - read_compound_fields: validate byte_offset+field_size against the compound's declared element size before slicing, instead of an unguarded out-of-bounds panic on a crafted member offset. - read_chunked_data/_cached/_sweep/_indexed: guard `ndims - 1` against underflow for a degenerate zero-dimension chunked layout. - copy_chunk_to_output: rewrite all offset/stride arithmetic (both the 1-D fast path and the general N-D path) to use checked_add/checked_mul, skipping an out-of-range row/chunk instead of panicking on overflow. Add a new cargo-fuzz target, fuzz_dataset_read, that walks every dataset in a parsed file via the clawhdf5 facade and exercises the contiguous/ chunked/compact raw-data read paths that the existing fuzz_full_file target doesn't reach. Seeded with the chunked/VDS/compound-relevant test fixtures plus two crash regressions found during this pass (the copy_chunk_to_output overflow and the ndims-1 underflow, both fixed above — this target found real bugs within the first couple of runs). Not wired into CI (nightly-only, multi-minute runs); documented in fuzz/README.md as a manual/scheduled check instead. Also fixed the README's stale rustyhdf5-format naming while touching this file. Added regression tests for every fix (near-usize::MAX offsets, the self-referencing B-tree case, the compound byte_offset overrun, the zero-dim layout, and both copy_chunk_to_output overflow paths) so these are caught by `cargo test`, not just the fuzz corpus.