docs(webapp): state that the debounce ceiling is a default, not an enforced limit

A trigger that sets maxDelay uses that value even when it is longer than
the configured ceiling, so the setting bounds only the triggers that omit
it. Say so where an operator reads it.

Author: matt-aitken

apps/webapp/app/env.server.ts

@@ -1045,7 +1045,9 @@ const EnvironmentSchema = z
      * trigger. Unset by default: a continuously triggered debounce key is pushed back for as
      * long as the triggers keep coming, and `debounce.maxDelay` on the trigger is the only
      * bound. Setting this applies a ceiling to every debounced run that does not carry its own
-     * `maxDelay`, and any `delay` at or above it stops runs from being pushed at all.
+     * `maxDelay`, and any `delay` at or above it is rejected at trigger time. It is a default
+     * rather than an enforced limit: a trigger that sets `maxDelay` uses that value even when it
+     * is longer than this.
      */
     RUN_ENGINE_MAXIMUM_DEBOUNCE_DURATION_MS: OptionalPositiveIntEnv,