v0.2.4

Documentation, tooling, and submodule-hygiene release — no change to the
simulation binary's behaviour.

Added

• scripts/check_doc_links.py plus a CI step that validates documentation
  links against the rendered mdBook page set, failing on links to pages
  absent from SUMMARY.md (which 404 on the published site). Replaces the
  previous file-existence-only check that missed this class of breakage.

Changed

• Migrated the eda-infra-rs and benchmark dataset submodules from the
  ChipFlow org to gpu-eda forks. eda-infra-rs was rebased onto its
  upstream (gzz2000/eda-infra-rs), picking up the upstream license-string
  fix; the integration patches (Metal + HIP backends, ANSI-port and unary-NOT
  parser support) now ride a jacquard-integration branch. The parser fixes
  were also submitted upstream.

Documentation

• Fixed published-site 404s by adding orphaned pages to the mdBook
  SUMMARY.md (project scope, timing correctness/validation, selective
  X-propagation, X-debugging, release process, cosim backend-portability and
  its phase plans, the JTAG debug server, netlist-graph xroots).
• Corrected stale "cosim is Metal-only" claims — cosim is now backend-portable
  (Metal/CUDA/HIP plus a CPU fallback) — and refreshed the Post-Phase-0
  roadmap status line.
• Removed the notional GF130 commercial-PDK codename across the docs.
• Refreshed the docs index (cosim Quick Reference; Known Issues now link to
  GitHub; pruned Future Documentation Needs) and pointed the README's doc
  links at the published mdBook.
• Fixed the ADR 0011 #80→#103 multi-SRAM cross-reference; folded the
  shipped cosim / CUDA-HIP timing implementation-plan docs into an ADR 0017
  amendment; repointed in-book links to repo files (CHANGELOG, tests,
  packaging) at GitHub URLs.