docs: meshing literature survey and the tet/hex pipeline it chooses (#1)

Survey of about 75 papers on robust predicates, Delaunay tetrahedralization, boundary
recovery, quality improvement and hexahedral meshing, with verified DOIs and the
licence of every associated code base. Architecture and roadmap now name the chosen
methods (robust CDT after Diazzi et al. 2023; octree-dual all-hex first). ADR 0001
adds the licence findings and the test-geometry rule.


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

@@ -39,6 +39,26 @@ CC0 and public domain.
 | Elmer | GPL-2.0 / LGPL-2.1 | multiphysics solver |
 | deal.II, FreeFEM, Salome | LGPL | FE libraries, pre-processing |
 | OpenCASCADE | LGPL-2.1 | B-rep kernel |
+| Attene's CDT, Indirect_Predicates, VolumeMesher | GPL / LGPL | robust CDT, indirect predicates (implement from the papers) |
+| TetWild (original), Evocube, robustPolycube, ultimaille, invertible-maps | GPL-3.0 / AGPL-3.0 | tet meshing, polycube, injective maps |
+| libHexEx, libHexHex, QGP3D, MC3D, CoMISo, Graphite | GPL | integer-grid-map hex extraction, quantization |
+| Shewchuk's Triangle | non-commercial only | 2D meshing |
+| geogram `third_party/tetgen`, `third_party/triangle` and their wrappers | AGPL / non-commercial | (the rest of geogram is BSD-3 and readable) |
+| libigl `copyleft/` modules | GPL | (libigl core is MPL-2.0 and readable) |
+| OpenVolumeMesh, CGoGN | believed LGPL, unverified | treat as forbidden until checked |
+
+**Repositories without a licence are all rights reserved: never read them** (for example Gao
+2019's octree hex code, LoopyCuts). Readable references for the meshing work (re-implement from
+the paper, note anything adapted in ATTRIBUTION.md): Shewchuk's `predicates.c` (public domain),
+`georust/robust` (Apache-2.0), geogram (BSD-3, exclusions above), fTetWild (MPL-2.0), CinoLib,
+Gen-Adapt-Ref, HexaLab, robust_hex_dominant_meshing (MIT), quartet (ISC). The full table with
+sources is in `docs/meshing/literature.md`.
+
+**Test geometry** follows the same rule as test data: nothing produced with a commercial CAD or
+CAE product. That excludes ABC (Onshape), MAMBO (files from commercial translators) and the HexMe
+models that come from ABC, GrabCAD or Siemens NX; HexMe's Gmsh-made models are allowed (CC-BY-4.0).
+Thingi10K (per-model Creative Commons licences, authoring tool unrecorded) is pending an owner
+decision. The default corpus is generated: SolidCraft-built parts and analytic shapes.
 
 **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'