C2: Fix coverage.sh — remove || true from lcov capture/extract steps so real
lcov failures are visible; empty coverage.info now exits with code 3.
C3: Add coverage gate to quality-gates CI job (SKIP_COVERAGE_GATE=1 ramp-up
mode until I5 is resolved — fast suite covers ~9.6% not 80%). Thresholds:
80% line / 70% branch / 90% function (agreed 2026-05-31).
V1: Wrap JSON parse + field extraction in try/catch — nlohmann parse_error and
type_error now surface as std::runtime_error with the file path.
V2: Wrap stoi/stod in XML Solver parser — missing/non-numeric attributes throw
std::runtime_error instead of leaking std::invalid_argument.
V4: Validate required JSON keys (dof_vector, solver, solver.*) before access —
missing field produces a clear named-field error message.
I2: 6 serialization negative tests (missing file, malformed JSON, missing
dof_vector, missing solver block, missing XML file, non-numeric XML attr).
I3: load_mesh throws on non-triangulated (quad) mesh — covers the
is_triangle_mesh guard that was previously untested.
I4: spherical_hessian throws on edge DOFs — covers the logic_error guard.
290/290 tests pass (+8 new).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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