PRE-SUBMISSION AUDIT -- NoDEA
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TITLE / POSITIONING
PASS: The title foregrounds rigorous stabilization and sharp decay rather than numerical application.
PASS: The main problem is a nonlinear differential-equation system with mixed boundary conditions.
NOTE: If the editor interprets "nonlinearly coupled" narrowly, a safer alternate title is:
      "Sharp Energy Decay and Indirect Stabilization for a Semilinear Wave-Diffusion System with Mixed Boundary Conditions."

MATHEMATICAL NOVELTY
PASS: Indirect damping only through the parabolic variable is explicit in the exact energy identity.
PASS: High-frequency spectral asymptotics identify the obstruction to exponential stability.
PASS: The upper resolvent growth O(|omega|^2) is paired with a spectral lower bound of the same order.
PASS: The strong-data energy exponent t^{-1} is therefore presented as sharp.
PASS: The nonlinear endpoint is NOT overclaimed; the manuscript states near-sharp t^{-1+2 epsilon} energy decay for small higher-order data.

WELL-POSEDNESS / ASSUMPTIONS
PASS: Positive-measure Dirichlet boundary gives Poincare coercivity and lambda_1>0.
PASS: Defocusing primitive F>=0 prevents energy blow-up at the Galerkin level.
PASS: Energy-subcritical growth is stated explicitly for d<=3.
PASS: Invariant-set argument clearly identifies the zero-dissipation set.
CAUTION: The strong-solution / nonlinear-rate theorem invokes the usual mixed-boundary elliptic regularity; for a merely Lipschitz domain, the manuscript explicitly allows replacement by fractional-domain embeddings.

DECAY THEORY
PASS: Modal characteristic polynomial checked independently by direct elimination.
PASS: Routh-Hurwitz condition: lambda(lambda+kappa^2)-lambda^2=lambda kappa^2>0.
PASS: Wave-root expansion gives Re(s) ~ -kappa^2/(2 lambda).
PASS: Resolvent determinant is written explicitly.
PASS: Borichev-Tomilov exponent mapping is consistent: resolvent |omega|^2 -> state norm t^{-1/2} -> energy t^{-1}.

NUMERICS
PASS: Figures are illustrative only; no theorem depends on them.
PASS: Reproducibility script included.
PASS: One-dimensional mixed eigenvalues lambda_n=((n+1/2)pi)^2 are exact.

REFERENCES
PASS: Core semigroup, PDE, and polynomial-stability references included.
PASS: Recent NoDEA papers on mixed boundary conditions, coupled evolution systems, and stability included.
CHECK BEFORE FINAL PORTAL UPLOAD: Springer metadata may auto-format journal references; retain DOI fields.

DECLARATIONS
PASS: Funding statement present.
PASS: Conflict-of-interest statement present.
PASS: Data availability statement present.
PASS: Code availability statement present.
PASS: Author-contribution statement present for sole author.

FORMATTING / PACKAGE
PASS: Main PDF compiled from editable LaTeX.
PASS: Figures supplied as vector PDF plus PNG previews.
PASS: Cover letter supplied as PDF and source.
PASS: Optional highlights supplied as plain text.
PASS: No external data files are required.

FINAL RISK ASSESSMENT
Scientific positioning: STRONG for NoDEA if the editor accepts the chosen model as sufficiently novel.
Primary desk-rejection risk: novelty relative to existing thermoelastic / indirectly damped hyperbolic-parabolic systems.
Mitigation already built into manuscript: exact mixed-boundary spectral asymptotics + matching sharp resolvent lower/upper bounds + nonlinear well-posedness/stabilization in one unified treatment.

NO ACCEPTANCE CAN BE GUARANTEED. The package is designed to maximize rigor, fit, and defensibility rather than promise an editorial outcome.
