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.

scripts/dev/lint

@@ -8,4 +8,15 @@ source "$(git rev-parse --show-toplevel)/scripts/_helpers.sh"
 
 ensure_working_directory!
 
-mix lint
+debug_msg "Formatting..."
+mix format
+
+debug_msg "Running credo..."
+mix credo
+
+debug_msg "Extracting translations..."
+mix gettext.extract --merge
+
+debug_msg "Running shellcheck..."
+fd . 'scripts/' --exclude '*.hurl' -t file --exec shellcheck --color
+fd . '.claude/hooks' -t file --exec shellcheck --color