cdktn: TerraformOutput precondition is accepted but never synthesized

[so0k]

Expected Behavior

TerraformOutput accepts a typed precondition (TerraformOutputConfig.precondition), so it should synthesize an output precondition block (JSON and HCL).

Actual Behavior

The property is stored and then silently dropped — no precondition in the synthesized output, no warning.

packages/cdktn/src/terraform-output.ts declares it (:26), keeps it (:35, :45), but neither synthesizeAttributes() (:99-106) nor synthesizeHclAttributes() (:108-137) emits it, and nothing else reads .precondition.

Steps to Reproduce

const env = new TerraformVariable(stack, "env", { type: "string" });
new TerraformOutput(stack, "out", {
  value: env.stringValue,
  precondition: { condition: Op.neq(env.stringValue, ""), errorMessage: "env must not be empty." },
});
// Testing.synth(stack) -> "out": { "value": "${var.env}" }   (no precondition; same with synthHcl)

Workaround

output.addOverride("precondition", [{ condition: "${...}", error_message: "..." }])

Anything Else?

• Related but distinct: fix(lib): HCL synth corrupts or drops core blocks (terraform{} extras, top-level overrides, lifecycle conditions) #313 (HCL-mode rendering of resource lifecycle.precondition/postcondition as an attribute list). The HCL path here should render repeated blocks, not an attribute list.
• Found while researching the terraform test RFC (cdktn-planning RFC 09): expect_failures = [output.<name>] is the way to test an output precondition, which is meaningless while the precondition is dropped. Prerequisite for that RFC.