rmerk gives med-mal records a real chronology view

rmerk's fork is being built for medical-malpractice work, where the first thing anyone wants from a stack of records is a clean date-ordered story of what happened to the patient. This phase adds a dedicated Timeline screen that reads work the system has already done on a document and renders it as a chronology you can click into - each event jumps to the underlying page and highlights the citation in the PDF. The bar the team set themselves was load in under two seconds with no language-model call on the critical path, and that's what shipped.

There's also a deliberate carve-out: mental-health records covered by Minnesota's § 144.293 are hidden behind a header toggle on top of server-side filtering, so they don't surface by accident. rmerk explicitly chose not to fold this into the existing per-document tabular review - one row per document can't honestly represent many encounters - and split medication, vitals and labs views into a follow-up.