Find every project-wide reference to a Module.fun[/arity].

Read-only consumer of Adze.ProjectRewrite's file enumeration — same source loading as rename / extract!, no mutation. Output is a per-file list of call sites, captures, and pipe references.

Scope

• Qualified calls — Module.fun(args), including the pipe-expanded form x |> Module.fun(args) and the bare-pipe form x |> Module.fun.
• Captures — &Module.fun/arity.
• Aliased references — alias Foo.Bar then Bar.fun(...), and alias Foo, as: F then F.fun(...), and brace-form alias Foo.{Bar, Baz}.

Not yet handled (intentional v1 limits):

• Unqualified calls via import Module — bare fun(args) after import is not detected. Imports rarely cross file boundaries in modern Elixir code; if this bites, file-local import scoping can be added later.
• Dynamic refs — apply/3, Module.concat(...), runtime module composition.
• String-literal mentions — comments, @moduledoc heredocs.

Output shape

%{
  target: %{module: "MyApp.Foo", function: :bar, arity: 2 | :any},
  total: 3,
  files: %{
    "lib/x.ex" => [
      %{line: 10, kind: :call,    arity: 2, snippet: "MyApp.Foo.bar(a, b)",
        in_module: "MyApp.Caller"},
      %{line: 15, kind: :capture, arity: 2, snippet: "&Foo.bar/2",
        in_module: "MyApp.Caller"}
    ]
  }
}

in_module is the innermost-enclosing defmodule name at the ref's position, or nil for top-level refs (scripts, .exs without defmodule).

Usage

iex> Adze.FindCallers.find_callers("MyApp.Foo.bar/2", mix_root: ".")
{:ok, %{target: ..., files: %{...}, total: 3}}

iex> Adze.FindCallers.find_callers({MyApp.Foo, :bar, :any},
...>   files: %{"lib/x.ex" => "..."})
{:ok, %{...}}