vdjtools 5.2.1

Adds source-preserving tcR ingestion with read_mitcr(..., collapse=False), including bestVGene/bestJGene aliases, missing or ambiguous gene calls, and repeated source rows.

Preserves exact nonnegative int64 counts through ingestion and shared schema normalization, including counts above 2^53 and decimal-zero notation. The default collapsed ingestion path is unchanged.

Validated with conversion/schema regression tests, clean-wheel ingestion checks, and the complete cross-platform dependency CI before release. Native scoring kernels and bundled models are unchanged.