net: re-address hub network 10.60.1.0/24 -> 192.168.8.0/24

The project was designed around a 10.60.1.0/24 travel-router network,
but the actual RemoteRig router uses 192.168.8.0/24 (the C6 associates
and gets 192.168.8.x; hub confirmed at 192.168.8.56). Replace the
network prefix everywhere (last octet preserved; GoPro 10.5.5.1 left
alone).

- scripts/setup-pi.sh: static IP 192.168.8.56/24, gateway 192.168.8.1,
  deploy/health command examples updated
- esp32-mqtt-bridge.cpp: default mqtt_broker -> 192.168.8.56
- firmware/data/config.json: broker -> 192.168.8.56 (wifi_password kept
  blank in git; real value flashed to the device only)
- docs (CONTEXT, MQTT_CONTRACT, READMEs, wireframes): gateway/hub/DHCP
  and example IPs re-addressed for consistency

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

firmware/README.md

@@ -14,7 +14,7 @@ Each camera node uses **two boards** connected via UART — zero network switchi
 │   (Camera Bridge)   │  RX←──────TX  │   (MQTT Bridge)      │
 │                     │    115200     │                      │
 │  STA → GoPro AP     │    8N1        │  STA → Travel Router │
-│  HTTP → 10.5.5.1    │               │  MQTT → 10.60.1.56│
+│  HTTP → 10.5.5.1    │               │  MQTT → 192.168.8.56│
 │  Start/stop/status  │               │  Hub registration   │
 └─────────────────────┘               └──────────────────────┘
 ```
@@ -22,7 +22,7 @@ Each camera node uses **two boards** connected via UART — zero network switchi
 | Board | Job | Network | Protocol |
 |-------|-----|---------|----------|
 | ESP8266 | Camera control | GoPro AP only (10.5.5.1) | HTTP → UART JSON |
-| ESP32 | Hub relay | Travel router only (10.60.1.x) | UART JSON → MQTT |
+| ESP32 | Hub relay | Travel router only (192.168.8.x) | UART JSON → MQTT |
 
 ## Quick Start
 
@@ -75,7 +75,7 @@ JSON-per-line at 115200 8N1. GPIO16 on both boards.
 |-----|---------|-------------|
 | `wifi_ssid` | `"RemoteRig"` | Travel router SSID |
 | `wifi_password` | `""` | Travel router password |
-| `mqtt_broker` | `"10.60.1.56"` | Pi Zero 2 W IP |
+| `mqtt_broker` | `"192.168.8.56"` | Pi Zero 2 W IP |
 | `mqtt_port` | `1883` | Mosquitto port |
 | `camera_id` | `""` | Assigned by hub on first announce (leave empty) |
 | `heartbeat_interval_sec` | `60` | MQTT heartbeat frequency |

firmware/data/config.json

@@ -1,7 +1,7 @@
 {
   "wifi_ssid": "RemoteRig",
   "wifi_password": "",
-  "mqtt_broker": "10.60.1.56",
+  "mqtt_broker": "192.168.8.56",
   "mqtt_port": 1883,
   "camera_id": "",
   "heartbeat_interval_sec": 60,

firmware/src/esp32-mqtt-bridge.cpp

@@ -41,7 +41,7 @@
 struct Config {
   String wifi_ssid       = "RemoteRig";
   String wifi_password   = "";
-  String mqtt_broker     = "10.60.1.56";
+  String mqtt_broker     = "192.168.8.56";
   int    mqtt_port       = 1883;
   String camera_id       = "";   // assigned by hub
   int    heartbeat_sec   = 60;