Refactor Result.Syntax and formatting across packages
- ocaml-gpt: Use Result.Syntax, add MBR integration, fuzz tests
- ocaml-mbr: Add fuzz tests, update .ocamlformat
- ocaml-matter: Use Result.Syntax in pase.ml
- ocaml-requests/h2: Use Result.Syntax in H/2 implementation
- ocaml-tm: Fix .ocamlformat version, apply formatting
- ocaml-x509: Use Result.Syntax in ASN.1 grammars and PKCS#12