docs(ten-moss): restore streamid_adapter hop in the diagram

The graph routes agora_rtc -> streamid_adapter -> stt; the diagram omitted the
adapter, which could mislead anyone mapping it to tenapp/property.json.

Author: HarshaNalluru

apps/ten-moss/README.md

@@ -13,6 +13,9 @@ caller speaks
 agora_rtc                  real-time audio transport (in / out)
   │
   ▼
+streamid_adapter           routes audio (PCM) frames to STT
+  │
+  ▼
 stt · deepgram             speech → text
   │  asr_result (final)
   ▼