3.9.0 - August 12, 2026

• perf: optimize immutable lookups, dictionary access, enumeration, and string slicing across Excel, HTML, PowerPoint, and Word (#444, #445, #448, #450, #451, #452, #454, #459, #462, #463, #466, #470)
• refactor: modernize core types and remove dead code/debug scaffolding from production and tests (#443, #456, #458, #459, #461)
• test(common): add StrictOoxmlTranslator coverage (#447)
• chore(deps): update SkiaSharp 4.150.1 → 4.151.1, TUnit 1.59.0 → 1.64.13, JsonSchema.Net 9.2.2 → 9.4.0, and System.CommandLine preview.5 → preview.7 (#442, #455, #457, #463, #467, #469)
• chore(ci): bump actions/setup-dotnet from 5 to 6 (#446)