* feat: add MappedSynchronizingHistoryProvider base class
Introduces an abstract class for history providers that handle symbol mapping and time-aligned data slices. Uses IMapFileProvider to resolve ticker changes, provides an abstract method for mapped history retrieval, and overrides GetHistory to synchronize results. Enables nullable reference types and adds documentation.
* Minor tweaks
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Co-authored-by: Martin Molinero <martin.molinero1@gmail.com>
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