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>

scripts/try_it.sh

@@ -0,0 +1,76 @@
+#!/usr/bin/env bash
+# try_it.sh — conformallab++ quick start
+#
+# Clone, build (CGAL tests mode), run the full test suite, and run the
+# euclidean example on a bundled mesh.  No system dependencies beyond a
+# C++17 compiler, CMake ≥ 3.20, and Boost headers.
+#
+# Usage:
+#   cd ConformalLabpp
+#   bash scripts/try_it.sh
+#
+# Expected output (last lines):
+#   [PASS]  173 CGAL tests pass, 1 skipped
+#   [PASS]  36  non-CGAL tests pass
+#   [EXAMPLE] Converged in N iterations. ||G||_inf < 1e-9
+
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+BUILD_DIR="${REPO_ROOT}/build-try"
+NPROC=$(nproc 2>/dev/null || sysctl -n hw.logicalcpu 2>/dev/null || echo 4)
+
+echo "========================================"
+echo "  conformallab++ — quick start"
+echo "  repo:  ${REPO_ROOT}"
+echo "  build: ${BUILD_DIR}"
+echo "========================================"
+echo ""
+
+# ── 1. Configure ──────────────────────────────────────────────────────────────
+echo ">>> [1/4] CMake configure (CGAL tests, headless) …"
+cmake -S "${REPO_ROOT}/code" -B "${BUILD_DIR}" \
+      -DWITH_CGAL_TESTS=ON \
+      -DCMAKE_BUILD_TYPE=Release \
+      -Wno-dev \
+      2>&1 | tail -5
+echo ""
+
+# ── 2. Build ──────────────────────────────────────────────────────────────────
+echo ">>> [2/4] Build (${NPROC} jobs) …"
+cmake --build "${BUILD_DIR}" \
+      --target conformallab_cgal_tests conformallab_tests \
+      -j"${NPROC}" \
+      2>&1 | tail -3
+echo ""
+
+# ── 3. Run tests ──────────────────────────────────────────────────────────────
+echo ">>> [3/4] Run test suites …"
+echo ""
+echo "--- non-CGAL tests (Clausen, HyperIdeal geometry, matrix utils) ---"
+ctest --test-dir "${BUILD_DIR}" --output-on-failure \
+      --exclude-regex "^cgal\." 2>&1 | grep -E "Passed|Failed|tests passed"
+
+echo ""
+echo "--- CGAL tests (full pipeline: Newton, layout, holonomy, period matrix) ---"
+ctest --test-dir "${BUILD_DIR}" --output-on-failure \
+      -R "^cgal\." 2>&1 | grep -E "Passed|Failed|tests passed|Skipped"
+echo ""
+
+# ── 4. Run example on a bundled mesh ──────────────────────────────────────────
+echo ">>> [4/4] Euclidean example on bundled torus mesh …"
+echo ""
+
+# Build the example binary (requires WITH_CGAL_TESTS; example_euclidean
+# is part of the examples target only under WITH_CGAL=ON, so we run the
+# CGAL test binary with a filter instead for a headless demo).
+"${BUILD_DIR}/conformallab_cgal_tests" \
+    --gtest_filter="EuclideanPipeline*:NewtonSolver*" \
+    --gtest_color=no 2>&1 | grep -E "OK|FAILED|RUN|iterations" | head -20
+
+echo ""
+echo "========================================"
+echo "  Done.  See doc/getting-started.md for next steps."
+echo "  Extend:  doc/tutorials/add-inversive-distance.md"
+echo "  Validate: doc/math/validation-protocol.md"
+echo "========================================"