Function accept_linear_solution 

pub fn accept_linear_solution(
    problem: &LinearProblem<'_>,
    plan: SolverPlan,
    solver_provider: SolverProvider,
    reason: ConvergenceReason,
    completed_iterations: usize,
    reported_residual_norm: f64,
    values: Vec<f64>,
) -> Result<LinearSolution, Diagnostic>

Independently verify and accept a backend-produced solution.

The backend supplies only operational evidence. Eqiora recomputes the initial and final residuals through the admitted operator, derives the target from the sole SolverPlan, and constructs the public report only after the true residual passes.

Errors

Returns EQ0802 for shape/non-finite operator behavior, inconsistent termination/iteration evidence, or when the true residual exceeds the declared target.