Correct iOS connectivity observability documentation (#12579)

* test: expose hidden mobile transport outages

* feat: export iOS network outcomes to Axiom

* Simplify mobile connectivity observability

* Bound connectivity observation state

* Harden connectivity observability delivery

* Bound mobile observability resources

* Flush every connectivity observation batch

* Fix network reporter background flush capture

* Preserve connectivity failure and retry semantics

* Harden terminal connectivity outcomes

* Keep concurrent connectivity starts separate

* Expose consent-bound network emitter

* Correlate host authentication latency

* Correlate concurrent connectivity starts by surface

* Fail closed when connectivity correlation is missing

* Keep connectivity event ingestion nonblocking

* Bound diagnostic telemetry intake

* Acknowledge emitted telemetry after ambiguous flush

* Keep relay policy latency observations enabled

* Record RPC readiness failures