Isolate execution observations and preserve injected error categories

docs/internal/generation.md

@@ -35,6 +35,12 @@ unknown usage. Transport, timeout, malformed, and noneligible status failures
 stop the sequence without retry exhaustion. Context is checked before each
 wait, acquisition, and dispatch.
 
+The public client adapter translates explicitly supplied public transport and
+malformed-response identities into internal categories while retaining the
+original error chain. This keeps injected attempt classifications consistent
+with terminal observations without parsing diagnostic text or retrying injected
+clients.
+
 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

docs/internal/observation.md

@@ -11,6 +11,12 @@ Prepared execution starts only after its private payload is atomically claimed;
 the facade receives that invocation's recorder privately and emits the terminal
 event after public error mapping. Failed claims and preparation emit nothing.
 
+The facade masks inherited recorder and prepared-claim state when entering
+preparation or execution. Delegated calls from an injected collaborator retain
+the caller's cancellation, deadline, and unrelated context values, but do not
+reuse the enclosing invocation's accounting. Only the new request's observer
+(or the claimed handle's retained observer) enables its observation lifecycle.
+
 A recorder keeps only counters, resolved identity fields, and the selected
 callback. It has no global history, queue, goroutine, or mutex held across a
 callback. The caller supplies normalized failure metadata; the recorder never