docs: verification and validation; published benchmarks; fixtures (#31)

* docs: verification and validation against theory, experiments and published benchmarks; fixtures

Owner decision 2026-10-13: test against experimental and theoretical data; results published by
vendors (e.g. Abaqus benchmark and verification manuals) may be used as cited reference values for
our own models of the same problems; once a case matches, its result becomes a fixture so fidelity
cannot regress. Commercial products are still never run and their files and text never copied.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* docs: V&V policy in AGENTS.md, ADR 0001 and the roadmap

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

---------

Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/adr/0001-libraries.md

@@ -89,8 +89,11 @@ dependency of `modelcraft-geometry` only behind its non-default `scripts` featur
 tooling (`modelcraft-testkit`) enables; the shipped library opens designs without it.
 
 **Commercial products** (Abaqus, Nastran, LS-DYNA, LS-PrePost, HyperMesh, ANSA, Femap, Patran,
-ANSYS) are never run, scripted or used as a source of data. Deck formats come from the vendors'
-public reference manuals, described in our own words with our own examples.
+ANSYS) are never run or scripted, and their input files, text and figures are never copied. Deck
+formats come from the vendors' public reference manuals, described in our own words with our own
+examples. Published numerical results (benchmark and verification manuals) may serve as cited
+reference values for our own models of the same problems (owner decision 2026-10-13;
+docs/verification.md).
 
 ## Consequences