v0.19.0

Added

• OXC.isolated_declarations/3 and isolated_declarations!/3 emit a TypeScript module's .d.ts from its source alone, as tsc --isolatedDeclarations would, through OXC's isolated declarations emitter. Exported declarations need explicit types, and the emitter reports those it cannot infer as TS9007-family errors. Options: strip_internal leaves out @internal declarations, sourcemap adds a declaration map (#8).