Align docs with ESP32-S3 dashboard architecture

docs/protocol.md

@@ -1,10 +1,10 @@
-# ESP32 ↔ Pico Communication Protocol
+# Legacy UART Communication Protocol
 
 ## Current Decision
 
-Primary communication is **UART over CAT5**.
+Primary dashboard communication is **WiFi HTTP API** between the Waveshare ESP32-S3 dashboard and the Cargo ESP32.
 
-Backup communication is the **ESP32 WiFi HTTP API**.
+This legacy UART protocol is retained for historical reference, diagnostics, simulator work, or alternate clients. It is not the current dashboard architecture.
 
 RS-485/MAX3485 is fallback-only and is not currently planned.
 
@@ -14,7 +14,7 @@ RS-485/MAX3485 is fallback-only and is not currently planned.
 * Baud: 115200
 * Format: 8N1
 * Framing: newline-delimited JSON
-* Direction: Pico dashboard ↔ ESP32 cargo controller
+* Direction: UART client ↔ ESP32 cargo controller
 
 ## Message Rules
 
@@ -28,7 +28,7 @@ Example:
 
 Responses should also be one JSON object followed by a newline.
 
-## Pico → ESP32 Messages
+## Client → ESP32 Messages
 
 ### Status Request
 
@@ -68,7 +68,7 @@ Expected response:
 }
 ```
 
-## ESP32 → Pico Messages
+## ESP32 → Client Messages
 
 ### Status Response