091 explicit label required when not punnable

// ============================================================================
// Test 210_091: MUST_RUN — explicit `name: value` form is REQUIRED (and must
//                         be accepted) when the value cannot pun to the same
//                         name. Guard against false positives in PARSE005.
//
// Cases covered (none should trigger PARSE005):
//   - Literal value:        echo(v: 5)
//   - Bare-name mismatch:   echo(v: other)        // last segment != 'v'
//   - Path mismatch:        echo(v: box.other)    // last segment 'other' != 'v'
//   - Expression value:     echo(v: 1 + 2)        // has operator at depth 0
//
// If any of these are rejected, PARSE005 has started over-firing and the rule
// has lost calibration. The negative twins live in 210_088/089/090.
// ============================================================================

~import std/io

~event echo { v: i32 } -> i32

~echo -> v

~event get-box { } -> { v: i32, other: i32 }

~proc get-box|zig {
    return .{ .v = 7, .other = 11 };
}

// Literal value — cannot pun, label required.
~echo(v: 5): r1 |> std/io:print.ln("literal: {{ r1:d }}")

// Expression value — cannot pun, label required.
~echo(v: 1 + 2): r2 |> std/io:print.ln("expr: {{ r2:d }}")

// Path mismatch — `box.other` puns to 'other', not 'v', so label required.
~get-box(): box |> echo(v: box.other): r3 |> std/io:print.ln("path mismatch: {{ r3:d }}")