wcraytor/mgcvUI: mgcvUI 0.2.0: All-Term Contribution Plots, Report Overhaul, Cross-Platform Hardening

Contribution plots for all model terms: interaction heatmaps (ti/te), factor-by-smooth multi-line plots, parametric scatter/bar charts — in UI and all report formats Predictor Settings table: checkbox columns grouped and relabeled (Include/Factor/Linear), vertical headers, bordered cells Reports (HTML/PDF/Word): equation section with f_i notation, all contribution plots, wrapped LaTeX equations, split ANOVA tables, transposed concurvity, tryCatch on every section Settings persistence: response_transform, cv, default_basis, default_k, tensor_type, optimizer, scale, discrete, nthreads now saved to SQLite Cross-platform: R >= 4.1 check, LaTeX/pandoc detection hides unavailable report formats, font download tryCatch with sans-serif fallback, SQLite graceful degradation, 3GB upload limit, temp dir writability check Fixed: unescaped JS double quote crashing app startup, gratia::appraise failures, LaTeX underscores in variable names, tryCatch scoping bug in officer doc assembly Documentation: User Guide appendix for system requirements and troubleshooting, README system requirements, vignette prerequisites