019 subflow multiline call

// ============================================================================
// PARSER BUG: Multi-line function calls in subflows break continuation parsing
// ============================================================================
//
// The parser fails to recognize continuation lines after multi-line function
// calls in subflow expressions. After the closing ')' of a multi-line call,
// the next '|' is treated as a "stray continuation line" instead of being
// recognized as part of the subflow.
//
// Expected: Parser should handle multi-line calls and continue parsing the flow
// Actual: Parser loses track of subflow context after ')'
//
// This bug was discovered while implementing benchmark 2101b_nbody_granular,
// which needed to pass multiple arguments to assemble_solar_system() across
// multiple lines.
//
// ============================================================================

const std = @import("std");

~event step_a { x: i32 }
| done { result: i32 }

~proc step_a {
    return .{ .done = .{ .result = x + 1 } };
}

~event step_b { a: i32, b: i32, c: i32 }
| done { result: i32 }

~proc step_b {
    return .{ .done = .{ .result = a + b + c } };
}

~event step_c { x: i32 }
| done { result: i32 }

~proc step_c {
    return .{ .done = .{ .result = x * 2 } };
}

// This subflow should work but currently fails
~event test_multiline_call {}
| final { result: i32 }

~test_multiline_call = step_a(x: 10)
| done a |> step_b(
    a: a.result,
    b: 20,
    c: 30
)
    | done b |> step_c(x: b.result)
        | done c |> final { result: c.result }

// Main flow
~test_multiline_call()
| final _ |> _