Record generation attempts and retry delays

docs/internal/generation.md

@@ -22,6 +22,14 @@ FIFO permit. Preparation failures dispatch nothing. When a positive retry
 budget ends with eligible failures, the internal exhaustion error retains the
 final cause and actual dispatched-attempt count.
 
+When an invocation-local [observation recorder](observation.md) is present in
+the context, each acquisition emits an attempt event, including canceled
+capacity waits without dispatch. Each actual retry wait emits a delay event,
+including interrupted waits. Active permits are released before callbacks;
+generation duration ends before callback delivery. Built-in successful-envelope
+usage retains reported-field presence, while injected clients use explicit
+presence when supplied and otherwise treat zero fields as unknown.
+
 Focused coordinator tests use controlled transport and wait functions. They
 cover eligibility, exhaustion, cancellation, backoff, request freezing, permit
 release, and the injected-client path. The capacity manager tests own permit