#115 docs: rework the README for readers adopting the table

• Usage and Configuring rewritten for adopters, with the rationale moved to Design notes
• Theming names Style Dictionary and the DTCG tokens
• Testing is split by kind of test, with fallow, Sonar and CodeQL under static analysis, and bundle size moves under Benchmarks
• the getRowId section is corrected
• Internationalization moves under Features, browser support gets its own section, and data attribution moves to the end

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Summary by cubic

Restructures the README without changing any code: rewrites Usage and Configuring for developers adopting the table, moves the rationale into a new Design notes section, names the Style Dictionary and DTCG token pipeline in Theming, nests Internationalization under Features, gives Browser support its own section, splits Testing into per-kind subsections with fallow, SonarCloud and CodeQL under static analysis, moves bundle size tracking under Benchmarks and data attribution to the end, and corrects the getRowId section to match the implementation.