feat: support orderBy on edge properties in query builder

[pdlug]

• Widen orderBy to accept edge aliases (keyof EdgeAliases) in addition to node aliases, allowing database-level ordering by properties on traversed edges
• Extract shared buildAliasToCteMap utility to correctly map edge aliases to the CTE of the node they are co-projected with
• Fix CTE alias resolution for edge aliases in buildStandardOrderBy, buildStandardGroupBy, and buildStandardVectorOrderBy

store.query()
  .from("Person", "p")
  .traverse("worksAt", "e")
  .to("Company", "c")
  .orderBy("e", "salary", "asc")  // now works — was a type error before
  .select((ctx) => ({ name: ctx.p.name, salary: ctx.e.salary }))
  .execute();

Closes #76