Phase 03: real CAM UPER codec + ESP32-C5 TX/RX serial link

- Firmware: rewrite obu-firmware TX loop to be serial-driven (no on-chip timer), add promiscuous RX + GeoNetworking/BTP unwrap (gn_unwrap.c), add binary UART framing to the phone (serial_link.c/.h). Drop local cam_encode() - CAM is now built on the phone.
- Kotlin: byte-exact UPER CAM encoder/decoder ported from cam.c (BitWriter/BitReader/CamUperCodec), matching SerialFrame codec, real UsbSerialTransport (usb-serial-for-android), CamTransmitLoop (1Hz base rate, event/geofence boost, ESP32-C5-only), wired into CamUseCaseRepository for RX and TripRecordingService for TX.
- Add V2X message retention: persist all CAM (own+remote) to Room while recording, drop otherwise (DB v2 -> v3 migration).
- Add jitpack repo + usb-serial-for-android dependency.

Fixes: UsbSerialTransport now uses SerialInputOutputManager.start()/stop() (this lib version manages its own thread internally) instead of manual Runnable/Thread submission, which didn't compile.

app/src/main/res/values-de/strings.xml

@@ -29,6 +29,7 @@
     <string name="dash_mqtt_error">Broker nicht erreichbar — V2X-Einstellungen prüfen</string>
     <string name="dash_recording">Aufnahme</string>
     <string name="dash_samples">Messwerte</string>
+    <string name="dash_start_driving_session">Fahrsitzung starten</string>
     <string name="dash_initialising">Wird initialisiert…</string>
     <string name="stat_pressure">Luftdruck</string>
     <string name="stat_altitude">Höhe</string>
@@ -61,6 +62,8 @@
     <string name="conn_bluetooth">Bluetooth</string>
     <string name="conn_bluetooth_phase3">Bluetooth</string>
     <string name="conn_bluetooth_phase3_desc">Bluetooth-Verbindung ist für Phase 03 geplant und noch nicht implementiert.</string>
+    <string name="conn_esp32_title">ESP32-C5 (USB Seriell)</string>
+    <string name="conn_esp32_phase3_desc">Die USB-Seriell-Verbindung zum ESP32-C5 ist für Phase 03 vorgesehen, aber noch nicht funktionsfähig — dafür muss zuerst das ESP32-Firmware-Protokoll nach Kotlin übersetzt werden.</string>
     <string name="conn_scan">Geräte suchen</string>
     <string name="conn_scanning">Suche läuft…</string>
     <string name="conn_usb_title">USB-C (Primär)</string>
@@ -119,6 +122,12 @@
     <string name="gnss_no_fix">Noch kein GPS-Signal — gehen Sie ins Freie</string>
     <string name="map_title">Standortkarte</string>
     <string name="map_location_label">Aktueller Standort</string>
+    <string name="v2x_map_remote_count">%1$d erfasste externe Verkehrsteilnehmer</string>
+    <string name="v2x_map_own_label">Eigen (Ego)</string>
+    <string name="v2x_map_remote_plain">Extern #%1$d</string>
+    <string name="v2x_map_remote_info">Extern #%1$d · Info</string>
+    <string name="v2x_map_remote_awareness">Extern #%1$d · Aufmerksamkeit</string>
+    <string name="v2x_map_remote_warning">Extern #%1$d · Warnung</string>
 
     <!-- Settings -->
     <string name="settings_title">Einstellungen</string>
@@ -151,6 +160,10 @@
     <string name="settings_connection">Verbindung</string>
     <string name="settings_usb_auto_detect">OBU per USB-C automatisch erkennen</string>
     <string name="settings_usb_manual_ip">OBU-IP (manuell)</string>
+    <string name="settings_obu_hardware">OBU-Hardware</string>
+    <string name="settings_obu_hardware_cit_one">CiT One</string>
+    <string name="settings_obu_hardware_esp32">ESP32-C5</string>
+    <string name="settings_obu_hardware_esp32_note">Die ESP32-C5-Unterstützung ist für Phase 03 vorgesehen, aber noch nicht funktionsfähig. Die CAM-Erzeugung wechselt zum Smartphone; USB-Seriell-Verbindung und DENM-Auslöser sind Platzhalter, bis das Firmware-Protokoll übersetzt ist.</string>
     <string name="settings_usb_transport">Aktiver Transport</string>
     <string name="settings_transport_usbc">USB-C</string>
     <string name="settings_transport_wifi">WLAN</string>
@@ -162,6 +175,8 @@
     <string name="mqtt_disconnect">Trennen</string>
     <string name="mqtt_auto_scroll">Automatisch scrollen</string>
     <string name="mqtt_no_topics">Noch keine Nachrichten</string>
+    <string name="mqtt_view_list">Liste</string>
+    <string name="mqtt_view_map">Karte</string>
     <string name="mqtt_no_topics_hint">Mit der OBU verbinden und auf V2X-Verkehr warten</string>
     <string name="mqtt_no_messages">Noch keine Nachrichten zu diesem Thema</string>
 
@@ -201,6 +216,7 @@
 
     <!-- Dashboard transport -->
     <string name="dash_transport_usbc">USB-C</string>
+    <string name="dash_transport_usb_serial">USB seriell</string>
     <string name="dash_transport_wifi">WLAN</string>
     <string name="dash_transport_bt">BT</string>
 

app/src/main/res/values/strings.xml

@@ -30,6 +30,7 @@
     <string name="dash_mqtt_error">Broker unreachable — check V2X settings</string>
     <string name="dash_recording">Recording</string>
     <string name="dash_samples">samples</string>
+    <string name="dash_start_driving_session">Start Driving Session</string>
     <string name="dash_initialising">Initialising…</string>
     <string name="stat_pressure">Pressure</string>
     <string name="stat_altitude">Altitude</string>
@@ -62,6 +63,8 @@
     <string name="conn_bluetooth">Bluetooth</string>
     <string name="conn_bluetooth_phase3">Bluetooth</string>
     <string name="conn_bluetooth_phase3_desc">Bluetooth connection is planned for Phase 03 and is not yet implemented.</string>
+    <string name="conn_esp32_title">ESP32-C5 (USB Serial)</string>
+    <string name="conn_esp32_phase3_desc">USB-serial connection to the ESP32-C5 is scaffolded for Phase 03 but not yet functional — it needs the ESP32 firmware protocol translated to Kotlin first.</string>
     <string name="conn_scan">Scan for Devices</string>
     <string name="conn_scanning">Scanning…</string>
     <string name="conn_usb_title">USB-C (Primary)</string>
@@ -120,6 +123,12 @@
     <string name="gnss_no_fix">No GPS fix yet — move to an open area</string>
     <string name="map_title">Location Map</string>
     <string name="map_location_label">Current Location</string>
+    <string name="v2x_map_remote_count">%1$d tracked remote road user(s)</string>
+    <string name="v2x_map_own_label">Own (ego)</string>
+    <string name="v2x_map_remote_plain">Remote #%1$d</string>
+    <string name="v2x_map_remote_info">Remote #%1$d · Info</string>
+    <string name="v2x_map_remote_awareness">Remote #%1$d · Awareness</string>
+    <string name="v2x_map_remote_warning">Remote #%1$d · Warning</string>
 
     <!-- Settings -->
     <string name="settings_title">Settings</string>
@@ -152,6 +161,10 @@
     <string name="settings_connection">Connection</string>
     <string name="settings_usb_auto_detect">Auto-detect OBU via USB-C</string>
     <string name="settings_usb_manual_ip">Manual OBU IP</string>
+    <string name="settings_obu_hardware">OBU Hardware</string>
+    <string name="settings_obu_hardware_cit_one">CiT One</string>
+    <string name="settings_obu_hardware_esp32">ESP32-C5</string>
+    <string name="settings_obu_hardware_esp32_note">ESP32-C5 support is scaffolded for Phase 03 but not yet functional. CAM generation moves to the phone; USB-serial connection and DENM trigger are placeholders pending firmware protocol translation.</string>
     <string name="settings_usb_transport">Active transport</string>
     <string name="settings_transport_usbc">USB-C</string>
     <string name="settings_transport_wifi">Wi-Fi</string>
@@ -163,6 +176,8 @@
     <string name="mqtt_disconnect">Disconnect</string>
     <string name="mqtt_auto_scroll">Auto-scroll to latest</string>
     <string name="mqtt_no_topics">No messages yet</string>
+    <string name="mqtt_view_list">List</string>
+    <string name="mqtt_view_map">Map</string>
     <string name="mqtt_no_topics_hint">Connect to the OBU and wait for V2X traffic</string>
     <string name="mqtt_no_messages">No messages on this topic yet</string>
 
@@ -202,6 +217,7 @@
 
     <!-- Dashboard transport -->
     <string name="dash_transport_usbc">USB-C</string>
+    <string name="dash_transport_usb_serial">USB Serial</string>
     <string name="dash_transport_wifi">Wi-Fi</string>
     <string name="dash_transport_bt">BT</string>