Add array support for local/export/readonly builtins

Add array length syntax ${arr[#]}

Map read path now expands variables before splitting on ., fixing map "$node" with dotted paths

Map assignment path uses quote-aware token splitting, enabling quoted keys like "--type="

Completion errors now display above prompt instead of being overwritten

Fix nested if/fi parser bug when closing keywords appear on separate lines

Add QuoteState enum, replacing ad-hoc quote tracking booleans across lexer, highlighter, and expansion

Add split_tk_at/split_tk for quote-aware token splitting with span preservation

Refactor setup_builtin to accept optional argv for deferred expansion

Add ariadne dependency (not yet wired up)

src/builtin/read.rs

@@ -75,7 +75,8 @@ pub fn read_builtin(node: Node, _io_stack: &mut IoStack, job: &mut JobBldr) -> S
 
   let (argv, opts) = get_opts_from_tokens(argv, &READ_OPTS)?;
   let read_opts = get_read_flags(opts).blame(blame.clone())?;
-  let (argv, _) = setup_builtin(argv, job, None).blame(blame.clone())?;
+  let (argv, _) = setup_builtin(Some(argv), job, None).blame(blame.clone())?;
+  let argv = argv.unwrap();
 
   if let Some(prompt) = read_opts.prompt {
     write(borrow_fd(STDOUT_FILENO), prompt.as_bytes())?;