Jurana moves to deterministic-first ledger ingestion

Jurana now reads time ledgers from known case management systems deterministically, detecting the format automatically rather than asking a user to map columns by hand. AI extraction is kept as the fallback for formats with no parser, and AI enrichment continues to layer on top where file notes can improve thin time entries.

The reason is simple. When a machine can be certain, it should be certain. Language models are for the parts of the problem that are genuinely ambiguous, not for re-reading a spreadsheet that has a schema.