082 unbalanced bracket in args

// TEST: A stray ']' (or ')') before its matching opener in a call's argument
//       list must be rejected LOUDLY at the parser, located at the user's
//       source line — not silently mis-split into malformed args that only
//       blow up later as an opaque Zig backend error pointing at generated code.
//
// MUST_ERROR: unbalanced
//
// `lexer.parseArgs` tracks paren/bracket depth as unsigned and previously
// CLAMPED a closer with no opener (`]` while depth==0) to zero. The imbalance
// was swallowed, the comma split fired anyway, and the orphaned ']' landed in
// the emitted Zig — surfacing as `error: expected expression, found ']'` at
// output_emitted.zig instead of here. Reject it at the earliest layer.
//
// NOTE: '<'/'>' are NOT covered — they are overloaded as comparison operators
// in Expression args, so their depth is intentionally clamped, not rejected.

~import std/io

~pub tor sum { xs: string } -> i32

~sum(xs: ]1, 2[): n |> std/io:print.ln("got")