/port-to-dune

Convert an ocamlbuild/topkg project to dune build system

# Port to Dune

This command migrates an OCaml project from ocamlbuild/topkg to dune.

## Arguments

None - operates on the current directory.

## Prerequisites

The command expects to find ocamlbuild artifacts:
- `_tags` - ocamlbuild compilation flags
- `*.mllib` files - module lists for libraries
- `pkg/pkg.ml` - topkg package description (optional)
- `pkg/META` - findlib metadata (optional)
- `opam` - package dependencies

## Migration Process

### 1. Analyze Existing Build

Read and parse:
- `_tags` - Extract package dependencies, compiler flags, thread usage
- `*.mllib` - Identify libr...