053 braceless continuation constructors

// Test: Braceless branch constructors in flow continuations
//
// This tests the identity branch constructor syntax INSIDE flows:
//   | branch r |> done           (empty identity)
//   | branch r |> result r.value (identity with expression)
//
// This complements 100_052 which tests subflow syntax.

~import "$std/io"

// Source event
~pub event compute { x: i32 }
| value { n: i32 }

~proc compute {
    return .{ .value = .{ .n = x * 2 } };
}

// Result event with identity branches
~pub event result {}
| ok i32
| fail

// Wrapper that uses braceless constructors in continuations
~pub event run_test {}
| done

~proc run_test {
    // This internally tests braceless continuation constructors
    return .{ .done = {} };
}

// Subflow using braceless identity in continuation
~event process { input: i32 }
| result i32

~process = compute(x: input)
| value v |> result v.n

// Main test
~std.io:print.ln("Testing braceless in continuation:")
~process(input: 21)
| result r |> std.io:print.ln("  Got result: {{ r:d }}")