Bytecode compiler panics on wrong arity for many built-ins #141

Motoko's arity audit in the #140 review found these crashes. All of them also reproduce on base, before #140.

Governed builds panic on: read_file (0 args), write_file (0–1), mkdir (0), env (0), task (0), res (0–2), res_json (0–1), store_open (0), defun (0–1), http_server (0), and (print (str_trim)).

Default profile only: exec, spawn_agent (0–1), llm_generate, sql_query (0–1), db_connect (0–2), lazy_synthesize (0–2), confidence.

Repro: echo '(cli_app (read_file))' > p.howl && howlframe build --profile governed p.howl -o o

Expected: a fail-closed arity error (suggested code ARITY_ERROR), no panic and no artifact, like #139.

Related gaps on the Go/JS targets: all/any, ver_gt/ver_ge and an if used as a value still print 'Built' but produce code that doesn't compile. These should be rejected with UNSUPPORTED_ON_TARGET.