0a343036d8
Completes requirement V1. A compound (multi-column) FK now routes a bus connector — each paired endpoint's stub merges into a shared vertical channel that splits to the other side — plus an explicit "(a, b) ▶ P.(x, y)" pairing line; the bus generalises the single-column jog (reproducing it exactly, so prior snapshots are unchanged). Self-referential FKs render as two same-named boxes. - output_render.rs: gutter_seg routes all endpoint pairs via a junction() bus; pairing line for compound FKs; compound, self-ref, and compound-from-data (build_diagram_table glue) tests + snapshots - compound_fk.rs: worker test that show_relationship carries both paired column lists into the diagram payload - db.rs: document do_show_one's now-app-superseded relationship prose branch (retained as a worker-API/text fallback; could back a future non-visual display option, cf. ADR-0044 OOS-7) Second /runda pass over the implementation: confirmed ADR-compliance, UTF-8/byte-range safety, and edge-case routing. The ADR §3 last-resort helper line was considered and rejected (vertical fallback + ratatui truncation cover all realistic cases). ADR-0044 marked implemented; requirements.md V1 -> [x]. Full suite 2207 pass / 0 fail / 1 ignored; clippy nursery clean.