fix(subagent): drop the dead reportDelivery destructure default

`apply()` resolved the deployment config through schemastery's `Config()`,
which always fills the schema default (`quiet`, pinned by the config test),
so the `= 'quiet'` destructure fallback was dead at runtime on every path —
and as a defaulted parameter it formed a branch no test could ever
exercise against the per-file coverage gate. Remove the fallback and let
the schema be the single home of the default.

packages/subagent/tool-subagent-report/src/index.ts

@@ -88,7 +88,7 @@ export function installReportTool(
  * @param config - deployment scheduling policy.
  */
 export function apply(ctx: Context, config: Config = {}): void {
-  const { reportDelivery = 'quiet' } = Config(config)
+  const { reportDelivery } = Config(config)
   ctx.subagents.registerContinuableSetup(childCtx =>
     installReportTool(childCtx, ctx, reportDelivery))
 }