fix(cli): use :init.get_plain_arguments directly, drop ADO_ARGS workaround

Burrito's Zig wrapper passes CLI args via native argv after -extra,
so :init.get_plain_arguments/0 returns them correctly with internal
whitespace preserved. The earlier ADO_ARGS env-var workaround (which
relied on String.split/2) was both unnecessary and lossy — env vars
are null-terminated C strings, so they can't carry args with
spaces losslessly.

Companion to deps/burrito commit removing the ADO_ARGS env-var
write from the Zig launcher.

Verified end-to-end:
- escript: 'ado prs diff "Employee Management" ...' parses correctly
- Burrito binary: same command parses correctly with whitespace
  in project name intact
- All 367 tests pass; Credo clean

Author: gilbertwong96

lib/ado_cli/application.ex

@@ -16,17 +16,11 @@ defmodule AdoCli.Application do
 
     {:ok, _pid} = Supervisor.start_link(children, strategy: :one_for_one)
 
-    # Burrito passes CLI args via ADO_ARGS env var (set by Zig wrapper).
-    # Falls back to System.argv() for escript/release boot.
-    args =
-      case System.get_env("ADO_ARGS") do
-        nil -> System.argv()
-        "" -> System.argv()
-        str -> String.split(str, " ")
-      end
+    # Burrito's Zig wrapper passes CLI args via native argv after `-extra`,
+    # so :init.get_plain_arguments/0 returns them directly with whitespace
+    # preserved (e.g. "Employee Management" stays intact as one token).
+    args = Enum.map(:init.get_plain_arguments(), &to_string/1)
 
-    # CliMate.CLI run/1 handles exit codes internally via System.halt(0)/halt(1).
-    # The exit code propagates to the Zig wrapper through the OS process exit.
     AdoCli.CLI.run(args)
 
     # Unreachable — CliMate always halts after execution.

lib/ado_cli/cli.ex

@@ -127,18 +127,18 @@ defmodule AdoCli.CLI do
   def main(args \\ nil) do
     start_finch()
 
-    # Burrito passes CLI args via ADO_ARGS env var (set by Zig wrapper).
-    # System.argv() in Burrito mode includes BEAM flags; prefer env var.
-    cli_args =
-      case System.get_env("ADO_ARGS") do
-        nil -> args || System.argv()
-        "" -> args || System.argv()
-        str -> String.split(str, " ")
-      end
+    # Burrito's Zig wrapper passes CLI args via native argv after `-extra`,
+    # so :init.get_plain_arguments/0 returns them directly with whitespace
+    # preserved. System.argv() in escript mode also has the args.
+    cli_args = args || System.argv() || plain_args()
 
     run(cli_args)
   end
 
+  defp plain_args do
+    Enum.map(:init.get_plain_arguments(), &to_string/1)
+  end
+
   def command_definition, do: @command
 
   @doc """