Module errors 

Error enums for the TinyQuant core.

Three enums cover the three architectural layers:

• CodecError — codec layer (config, codebook, quantize, compress)
• CorpusError — corpus aggregate layer
• BackendError — backend/search layer

All variants are Clone + PartialEq so they can be threaded through Arc and matched in tests.

See docs/design/rust/error-model.md for the full taxonomy, Python-exception mapping, and FFI conversion table.

Enums

BackendError

Errors produced by the search-backend layer.

CodecError

Errors produced by the codec layer.

CorpusError

Errors produced by the corpus aggregate layer.