Move lint, precommit, shellcheck from mix aliases to mise scripts

Mix aliases should only compose mix tasks. Shell tool orchestration
(shellcheck, fd) belongs in mise scripts. This removes the mix cmd
escape hatch and makes the boundary clear: mix.exs for pure mix
composition, scripts/ for cross-toolchain orchestration.

mix.exs

@@ -27,12 +27,6 @@ defmodule MusicLibrary.MixProject do
     ]
   end
 
-  def cli do
-    [
-      preferred_envs: [precommit: :test]
-    ]
-  end
-
   # Specifies which paths to compile per environment.
   defp elixirc_paths(:test), do: ["lib", "test/support"]
   defp elixirc_paths(_), do: ["lib"]
@@ -142,15 +136,6 @@ defmodule MusicLibrary.MixProject do
   # See the documentation for `Mix` for more info on aliases.
   defp aliases do
     [
-      precommit: [
-        "shellcheck",
-        "credo --strict",
-        "sobelow --compact --exit",
-        "gettext.extract --check-up-to-date",
-        "format --check-formatted",
-        "deps.unlock --unused",
-        "test"
-      ],
       setup: [
         "deps.get",
         "ecto.setup",
@@ -161,16 +146,6 @@ defmodule MusicLibrary.MixProject do
       ],
       "ecto.setup": ["ecto.create", "ecto.migrate"],
       "ecto.reset": ["ecto.drop", "ecto.setup"],
-      shellcheck: [
-        "cmd fd . 'scripts/' --exclude '*.hurl' -t file --exec shellcheck --color",
-        "cmd fd . '.claude/hooks' -t file --exec shellcheck --color"
-      ],
-      lint: [
-        "format",
-        "credo",
-        "gettext.extract --merge",
-        "shellcheck"
-      ],
       # When running the migrate task WITHOUT setting the log_level option,
       # Ecto defaults to debug IRRESPECTIVELY of the log level set in
       # config/test.exs. The debug log level persists while the first 2-3