docs: remove vehicle-specific Xterra branding

docs/API.md

@@ -880,7 +880,7 @@ Updates the AP SSID/password and restarts the access point.
 Example request:
 
     {
-      "ssid": "Xterra-Camp",
+      "ssid": "Overland-Controller",
       "password": "new-secure-password"
     }
 

docs/ARCHITECTURE.md

@@ -1,6 +1,6 @@
 # Architecture
 
-Overland Controller is a distributed monitoring and control platform for the Nissan Xterra and future mobile power systems.
+Overland Controller is a distributed monitoring and control platform for mobile power systems and overland vehicles.
 
 Core principle:
 

docs/archive/codex-handoff.md

@@ -1,4 +1,4 @@
-# Xterra Overland Dashboard - Codex Handoff
+# Overland Controller - Codex Handoff
 
 ## Repository
 
@@ -27,7 +27,7 @@ Before making any code changes:
 
 # Project Overview
 
-The project is an overland vehicle monitoring and control system for a Nissan Xterra.
+The project is an overland vehicle monitoring and control system for a overland vehicle.
 
 Architecture:
 

docs/archive/pico-architecture.md

@@ -2,7 +2,7 @@
 
 ## Purpose
 
-The Raspberry Pi Pico 2 W dashboard is the primary user interface for the Xterra Overland Power & Monitoring Dashboard.
+The Raspberry Pi Pico 2 W dashboard is the primary user interface for the Overland Controller dashboard.
 
 Its responsibilities are:
 

docs/archive/uart.md

@@ -4,7 +4,7 @@
 
 The first hardware version will use UART over CAT5 between the Pico dashboard and the ESP32 controller.
 
-UART is simpler than RS-485 and should be reliable for the short cable run inside the Xterra.
+UART is simpler than RS-485 and should be reliable for the short cable run inside the vehicle.
 
 RS-485 remains a future fallback if testing reveals communication issues.