Gauss-Riemann Spectral Calculus, Part I: Source, Bridges, Certificates, and Degeneration Chains

Part I of the first Gauss-Riemann Spectral Calculus (GRSC) programme series contains Papers 1-5. It records the source layer, the first bridge from continuous curvature images to discrete coherence readings, the Euler-to-Riemann second route, fixed-precision certificates for exploratory mathematics, and four-point degeneration chains. The package is presented as a public programme artifact: bridge, interface, certificate, and degeneration-chain results are separated from any final classical Landau-value claim.