Merge branch 'feat/p1-layout-v1v2' into fix/p1-read-gaps

docs/known-issues.md

@@ -78,12 +78,20 @@ the VDS item, which is marked.
 
 - **Layout message versions 1 and 2** (HDF5 1.6-era files): 84 of the 686
   sweep files, `InvalidLayoutVersion`. This is the largest single gap.
+  **Fixed 2026-09-25:** versions 1 and 2 are parsed (compact, contiguous,
+  chunked via the v1 B-tree).
+- **Compound datatype version 1 array members** (found with the layout
+  fix; pre-1.4 files such as `tarrold.h5`): **wrong data** — the legacy
+  per-member dimensions were skipped, so an array member read as one scalar.
+  **Fixed 2026-09-25.**
 - **Virtual datasets:**
   - **Wrong data:** unmapped regions read as 0 instead of the fill value.
   - `%b` printf-style source names are not expanded.
   - Hyperslab selection versions 1 and 2 are refused.
 - **Files with a user block:** the base address is not applied.
 - **Old-style shared messages (version 1)** read the wrong address.
+  **Fixed 2026-09-25:** the address follows the link-name offset of the
+  embedded symbol table entry.
 - **Groups and links:**
   - Groups with a user-defined link type (e.g. 187) cannot be listed.
   - Dense groups with more than about 22 000 links cannot be listed.