chore: update diagnose.sh for dual-T3U WiFi and Android app

- Network section now checks wlan1 (in-car AP, 10.42.0.1), wlan2 (uplink),
  and reports wlan0 as retired fallback (was: first-wlan guess)
- Header + manual commands reflect current layout: Android companion app,
  remote server at yaris.ceaf.dev, AP/uplink nmcli profiles

scripts/diagnose.sh

@@ -7,6 +7,15 @@
 # Without --fix : read-only health check, prints a report, exits 0 if healthy.
 # With    --fix : attempts to auto-fix every issue it finds. Safe to run while
 #                 the service is running — restarts are done with systemctl.
+#
+# Current project layout (2026-08):
+#   Pi (Raspberry Pi 3) — Flask web UI + SQLite + OBD/GPS/dashcam, hosted as a
+#     5GHz AP on wlan1 (T3U #1, 10.42.0.1); internet uplink on wlan2 (T3U #2,
+#     home WiFi "BuzzBis" or phone hotspot); onboard wlan0 retired to fallback.
+#   Android companion app — connects to http://10.42.0.1 over the hotspot for
+#     the live dashboard + dashcam downloads, uploads to the remote server
+#     (https://yaris.ceaf.dev) over the phone's own cellular link.
+#   Remote server — self-hosted Flask+Postgres stack (unraid, yaris.ceaf.dev).
 # =============================================================================
 set -euo pipefail
 
@@ -129,17 +138,48 @@ fi
 # ── 3. Network ────────────────────────────────────────────────────────────────
 section "3. Network & Hotspot"
 
-# Hotspot (wlan0 or wlan1)
-HOTSPOT_IFACE=$(ip -o link show | awk '/wlan/{print $2}' | tr -d ':' | head -1)
-if [ -n "$HOTSPOT_IFACE" ]; then
-    HOTSPOT_IP=$(ip -4 addr show "$HOTSPOT_IFACE" 2>/dev/null | awk '/inet /{print $2}' | head -1)
-    if [ -n "$HOTSPOT_IP" ]; then
-        pass "WiFi interface $HOTSPOT_IFACE has IP $HOTSPOT_IP"
+# In-car AP lives on wlan1 (T3U #1, 5GHz @ 10.42.0.1). The Android app and the
+# phone browser connect to this for the live dashboard + dashcam downloads.
+AP_IFACE="wlan1"
+if ip -o link show | grep -q "^[0-9]*: $AP_IFACE:"; then
+    AP_IP=$(ip -4 addr show "$AP_IFACE" 2>/dev/null | awk '/inet /{print $2}' | head -1)
+    if [ -n "$AP_IP" ]; then
+        pass "In-car AP up on $AP_IFACE ($AP_IP)"
+        if echo "$AP_IP" | grep -q "10.42.0.1/"; then
+            pass "  AP is on the expected 10.42.0.1/24 subnet"
         else
-        warn "WiFi interface $HOTSPOT_IFACE has no IP address"
+            warn "  AP IP is $AP_IP — expected 10.42.0.1/24"
+        fi
+    else
+        fail "In-car AP interface $AP_IFACE has no IP — hotspot down?"
+        fix_action "bring up the AP profile" "sudo nmcli con up Hotspot-local"
     fi
 else
-    warn "No WiFi interface detected"
+    fail "AP interface $AP_IFACE missing — is T3U #1 plugged in?"
+fi
+
+# Internet uplink lives on wlan2 (T3U #2) — home WiFi "BuzzBis" or phone hotspot.
+UL_IFACE="wlan2"
+if ip -o link show | grep -q "^[0-9]*: $UL_IFACE:"; then
+    UL_IP=$(ip -4 addr show "$UL_IFACE" 2>/dev/null | awk '/inet /{print $2}' | head -1)
+    UL_SSID=$(nmcli -t -f GENERAL.CONNECTION device show "$UL_IFACE" 2>/dev/null | sed 's/GENERAL.CONNECTION://' || true)
+    if [ -n "$UL_IP" ]; then
+        pass "Uplink up on $UL_IFACE ($UL_IP${UL_SSID:+ via $UL_SSID})"
+    else
+        warn "Uplink interface $UL_IFACE has no IP (normal when out of WiFi/phone range)"
+    fi
+else
+    warn "Uplink interface $UL_IFACE missing — second T3U not plugged in?"
+fi
+
+# Onboard BCM43438 (wlan0) is retired to a weak fallback — informational only.
+if ip -o link show | grep -q "^[0-9]*: wlan0:"; then
+    W0_IP=$(ip -4 addr show wlan0 2>/dev/null | awk '/inet /{print $2}' | head -1)
+    if [ -n "$W0_IP" ]; then
+        info "Onboard wlan0 active ($W0_IP) — normally retired to fallback"
+    else
+        info "Onboard wlan0 present but inactive (retired fallback)"
+    fi
 fi
 
 # Is the web UI reachable locally?
@@ -353,6 +393,10 @@ section "8. Manual Recovery Commands"
 info "Restart service:          sudo systemctl restart $SERVICE"
 info "View live logs:           tail -f $LOG_FILE"
 info "Journalctl logs:          sudo journalctl -u $SERVICE -f"
+info "Bring up AP (wlan1):      sudo nmcli con up Hotspot-local"
+info "Bring up uplink (wlan2):  sudo nmcli con up home-wifi"
+info "Phone app URL:            http://10.42.0.1/  (hotspot) — Android app in ./android"
+info "Remote server:            https://yaris.ceaf.dev"
 info "Force OBD_PROTOCOL=6:     sudo systemctl edit $SERVICE"
 info "  (add: Environment=OBD_PROTOCOL=6  then restart)"
 info "Skip voltage check:       sudo systemctl edit $SERVICE"