ocaml-cbor: drop make_/make naming, add Sort + Error tests
- E332: collapse [Error.make] into [Error.v] by making [meta] an
optional argument with [Loc.Meta.none] as the default. The single
primary constructor [v] now serves both the location-aware and
result-only call sites.
- E331: rename the eight result-style helpers from [make_<kind>] to
[<kind>_result], avoiding the collision with the existing raising
helpers ([type_mismatch], [missing_member], etc.) that share the
unprefixed name. Update all 55 call sites in [lib/cbor.ml]
accordingly.
- E605: add [test/test_sort.ml] and [test/test_error.ml] so each
library module has a matching test file. Wire them into [test.ml]
and add [astring] to the test dune.
- E005: factor the duplicated "expected 4-element array" Error
construction in [tuple4] into a local [bad_arity] helper so the
function fits under the 54-line threshold.
Every existing test still passes. The 12 [Obj.magic] sites in
[lib/cbor.ml] are intentionally left untouched: they implement
runtime polymorphic dispatch that wants a typed redesign (GADTs or
explicit per-sort dispatch) and warrants its own thread.