P10 complete: packaging verified on fresh x86_64 and aarch64 VMs

Wheels (pure + manylinux_2_28 kernels), sdist, Docker image and conda packages built and
installed on fresh Ubuntu 24.04 machines; 225 unit tests pass against the installed
package; the tutorial runs with pip (with and without kernels); GTC/VCF content digests are
identical across pip, Docker and conda on both architectures and equal to the Pi's run.
docs/validation/P10.md; guide: install from wheels, Docker, conda; exit code 141.

CHANGELOG.md

@@ -1,6 +1,13 @@
 # Changelog
 
-## Unreleased (P9)
+## Unreleased (P9, P10)
+
+**Packaging (P10).** `scripts/build_dist.sh` (sdist, pure wheel, manylinux_2_28 kernel wheels for x86_64 and
+aarch64), `Dockerfile`, conda recipes (`packaging/conda/`). Verified on fresh x86_64 and aarch64 VMs: pip, Docker
+and conda installs give identical outputs (`docs/validation/P10.md`). A closed stdout pipe now exits 141 silently
+instead of reporting an internal error.
+
+**Performance (P9).**
 
 Optional compiled kernels `rust/simurg-core` (PyO3): fused GenCall calling and BAF/LRR, libm maps with CPython
 semantics, normalization nearest-neighbour searches, BPM parser. Byte-identical outputs to the pure-Python paths