Wi-Fi over USB tab for firmware with the USB console (v13)

Writes / reads / removes the box's Wi-Fi over the serial port with the
usb_console commands (kota ping, wifi set|get|clear, health) and follows
the box through the restart until it joins the network. The password is
sent hex-encoded and never logged.

firmware/ now holds merged-binary-v13.bin (build 3ae273ec) instead of the
previous 1.0.16 build; error_ids.csv synced with the firmware.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

kota_tech/diag/engine.py

@@ -335,6 +335,8 @@ class DiagnosticsEngine:
         self.matter_qr: str | None = None       # "KOTA: matter ... qr=MT:..."
         self.matter_manual: str | None = None
         self.kota_seen = False                  # firmware prints KOTA: lines
+        self.console_api: int | None = None     # "cmd ping ... api=N": box accepts USB commands
+        self.wifi_config: dict[str, str] | None = None   # last "cmd wifi_get" reply (never a password)
         self._reset_led_state()
 
     def _reset_led_state(self) -> None:
@@ -714,6 +716,20 @@ class DiagnosticsEngine:
             fd = self._custom(key, Severity[sev.upper()], title, meaning, actions, expl)
             self._touch(fd, line)
 
+    def _kota_cmd(self, line: LogLine, f: dict[str, str]) -> None:
+        """Replies to commands sent by this tool (firmware usb_console)."""
+        name = line.words[0] if line.words else ""
+        if f.get("ok") != "1":
+            return                                  # the Wi-Fi tab reports failures itself
+        if name == "ping":
+            api = f.get("api", "")
+            self.console_api = int(api) if api.isdigit() else None
+        elif name == "health":
+            self.boot.kota["health"] = line         # same fields as the periodic health line
+            self._kota_health(line, f)
+        elif name == "wifi_get":
+            self.wifi_config = {k: f.get(k, "?") for k in ("ssid", "password_set", "mode")}
+
     def _kota_led(self, line: LogLine, f: dict[str, str]) -> None:
         if "previous_boot" in line.words:
             code = f.get("code", "0")
@@ -845,6 +861,12 @@ class DiagnosticsEngine:
         if ln := k.get("mic"):
             on = ln.fields.get("enabled") == "1"
             out.append(("Microphone", "on" if on else "switched OFF (switch on the back)", "ok" if on else "info"))
+        if self.wifi_config:
+            from ..serialio.commands import unhex_utf8
+            w = self.wifi_config
+            ssid = unhex_utf8(w["ssid"])
+            out.append(("Wi-Fi config", (f"network '{ssid}', password {'set' if w['password_set'] == '1' else 'NOT set'}"
+                                         if ssid else "no network on the SD card") + f", mode {w['mode']}", "info"))
         if ln := k.get("health"):
             f = ln.fields
             wifi = f.get("wifi", "?")