92cda13ae4
Removes the `codec` and `limits` modules, eliminating manual serialization logic and OS file descriptor limit queries. Introduces a shared `append_path_suffix` utility to standardize path manipulation across `meta.rs` and `unitig_index.rs`. Refactors the file pool to dynamically size based on available file descriptors and optimizes descriptor lifecycle to prevent leaks. Enhances `SKFileReader` with LRU eviction, consumption tracking, and seek-on-reopen support. Migrates related round-trip and EOF tests to the reader module and updates chunking logic in the unitig index.