Add per-project socket limit and Revit socket device-type flag

- Project setting maxSocketsPerCircuit (migration 0018,
  project.update-settings schema 4, snapshot schema 11); older command
  and snapshot versions keep or upgrade the value to null.
- Revit configuration schema 2 marks device types as socket; version 1
  stays readable and derives the flag from socketCount family rules.
- Settings dialog field and device-type card on the Revit page.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/db-verify-circuit-schema.js

@@ -98,6 +98,7 @@ const requiredProjectColumns = [
   "work_stage",
   "project_lead",
   "project_editor",
+  "max_sockets_per_circuit",
 ];
 const projectColumns = new Set(
   db.prepare("PRAGMA table_info(projects)").all().map((column) => column.name)