SPAR native-support validation and boundary tests v2.3.0

Data and reproducibility package for “Native-Support Forecasting of Delivered EGMS Level-3 Displacement Values”. Version v2.3.0 adds the frozen uniform all-cell SPAR configuration; pre-specified E32N34 partitions 47–50; persistence, DLinear, LASSO, and causal-TCN comparisons; three same-origin within-tile replications; four shortened-history temporal counter-tests; ten analytic matched-interpolation controls; sampler and anchor ablations; direct predictions; source, configuration, and output hashes; and regenerated paper figures. The primary endpoint is the next delivered EGMS Level-3 value at valid product cells. The release does not claim independent geodetic truth, cross-region transfer, temporal universality, or Europe-wide superiority. Frozen GitHub commit: 9865ac6c107804abd127f32c4ad76140b497a52d. Deterministic archive SHA256: 6b0138c4c00cb79a1259dadfe01b8d2e34399bcf36abff7ace8ce1027cbc79fc. Transformer, STGCN, graph-model, and RSASE experiments are outside this release. Redistributed EGMS content should be acknowledged as European Union Copernicus Land Monitoring Service information; https://egms.land.copernicus.eu/.