chore/docs: Onboarding-Sprint für externe Mathematiker

- LICENSE: Copyright Tarik Moussa <Tarik.moussa95@gmail.com> (war user2595)
- CITATION.cff: maschinenlesbares Zitat mit 3 Primärreferenzen (Sechelmann 2016,
  Springborn 2020, Bobenko–Springborn 2004)
- scripts/try_it.sh: Clone→Build→Test→Beispiel in einem Skript
- doc/math/software-landscape.md: Landkarte aller relevanten Tools,
  Problem-A vs. Problem-B Abgrenzung, vollständige Feature-Matrix
- doc/math/novelty-statement.md: formales Alleinstellungsmerkmal,
  Zielgruppen, was dieses Projekt nicht ist
- code/CMakeLists.txt: cmake --install Target für Header-only-Library
- doc/getting-started.md: Testzähler 158→173, Beispiel-Output, try_it.sh
- README.md: CI/License/DOI-Badges, Cite-Abschnitt, Issue-Tracker-Link,
  Copyright, neue Doku-Einträge software-landscape + novelty-statement

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

doc/getting-started.md

@@ -60,7 +60,7 @@ cmake --build build --target conformallab_cgal_tests -j$(nproc)
 ctest --test-dir build -R "^cgal\." --output-on-failure
 ```
 
-Expected: **158 tests pass, 2 skipped** (intentional stubs for Phase 9 items).
+Expected: **173 tests pass, 1 skipped** (intentional stub for analytic HyperIdeal Hessian, Phase 9b).
 
 ### Mode 3 — Full local build (CLI app + interactive viewer)
 
@@ -125,6 +125,29 @@ After a full build (`-DWITH_CGAL=ON`):
 
 `example_layout.cpp` is the best starting point — it shows the complete pipeline in ~120 lines.
 
+**Expected output of `example_euclidean` on the built-in quad-strip mesh:**
+```
+[example_euclidean] No input file given — using make_quad_strip().
+[example_euclidean] Mesh: 6 vertices, 4 faces.
+[example_euclidean] DOFs: 5 (1 vertex pinned).
+[example_euclidean] Solving Newton system…
+[example_euclidean] Converged in 1 iterations.  ||G||_inf = 0
+[example_euclidean] Per-vertex conformal factors u_i:
+  v0  u = 0  (pinned)
+  v1  u = -1.38778e-17       ← ≈ 0 (machine epsilon)
+  ...
+[example_euclidean] Mesh saved to: /tmp/conformallab_euclidean_out.off
+```
+Convergence in 1 iteration is expected: the "natural equilibrium" construction
+sets x* = 0, so a small perturbation (-0.05) needs only one Newton step.
+
+**Quick automated start (no interactive build needed):**
+```bash
+bash scripts/try_it.sh
+```
+This clones nothing (run from inside the repo), builds the CGAL test suite, runs
+all 173+36 tests, and prints a summary.  See `scripts/try_it.sh` for details.
+
 ---
 
 ## Known issues