functions.create/retrieve fails for multi-word argument types

[hsusul]

Bug

functions.retrieve({ args }) (and therefore functions.create, which retrieves after create) resolves each arg to a type by taking only the last space-separated token and casting it to regtype:

STRING_TO_ARRAY(arg, ' ')[last]::regtype

That breaks SQL-standard multi-word types:

arg	last token	result
double precision	precision	invalid type name "precision"
timestamp with time zone	zone	error
x double precision	precision	error

Repro

await pgMeta.functions.create({
  name: 'test_multiword_arg',
  schema: 'public',
  args: ['x double precision', 'ts timestamp with time zone'],
  definition: 'select x',
  return_type: 'double precision',
  language: 'sql',
  behavior: 'STABLE',
  security_definer: false,
})
// CREATE succeeds; retrieve-by-args fails → create returns an error

Expected

Args should resolve using the full type name (and drop only an optional leading parameter name), so Studio/API can create and look up functions with common SQL types.