Migration 007 introduces the v5 routing primitive:
- clamps table (project-scoped, optional frame_id, excalidraw_id).
- cable_clamps join (cable_id, clamp_id, ord) with PK on (cable_id, ord)
and UNIQUE (cable_id, clamp_id) to block a clamp visiting the same
cable twice.
Store helpers in internal/db/clamps.go:
- CreateClamp / GetClamp / ListClamps / UpdateClamp / DeleteClamp —
standard project-scoped CRUD. UpdateClamp uses FrameRef tri-state.
- AttachClampToCable — appends or inserts at a given ord. Mid-sequence
inserts use a two-pass shift (bump by 10000, settle to ord+1) since
SQLite UPDATE doesn't support ORDER BY and a single bulk +1 would
collide with the UNIQUE (cable_id, ord) PK.
- DetachClampFromCable — removes the row then closes the gap.
- ReorderCableClamps — replaces the whole sequence in one tx.
- ListClampsForCable / ListCableClamps — read helpers.
Snapshot now carries clamps + cable_clamps arrays so the frontend can
hydrate everything in one call.
Tests cover create / update / cascade-delete / attach (append + insert
+ duplicate-rejected) / detach (gap closes) / reorder / snapshot.
