processors.py event_accepted signal: 9 skip conditions and dedup layering

In src/sentry/ingest/consumer/processors.py, event_accepted.send_robust() (lines 313-316) is skipped by 9 paths: (1) cache dedup hit at l.117-131 (ev:{project_id}:{event_id}, ~1h TTL), (2) store.load-shed-pipeline-projects kill switch (l.144), (3) orjson.loads failure OUTSIDE try block (l.150 — propagates unhandled, not wrapped as Retriable), (4) store.load-shed-parsed-pipeline-projects kill switch (l.175), (5) reprocess_only_stuck_events + missing from processing_store (l.188), (6) reprocess_only_events_not_in_nodestore + event IS in nodestore (l.192-196, d7fcb07bc42), (7) Organization.DoesNotExist (l.246), (8) client_ip filter (l.232), (9) any exception in try block — caught at l.317 and re-raised as Retriable. Trap: dedup cache catches most repeats; the reprocess flag is the SECOND filter, only catching dedup-escapees. send_robust swallows receiver exceptions. event_accepted semantically means "saved" not "seen"; consumers needing all traffic must use Kafka directly.