feat(ui-lvgl): roadmap stage 3 - message history on SD, Storage screen, saved trails

- Message history archived per conversation on the SD card (HIST_ARCHIVE):
  restored on boot, Older/Newer paging in threads, kept count selectable
- Settings > System > Storage: card and flash usage, breakdown by maps,
  messages, trails and other, kept-per-chat setting, delete history;
  reads the mounted volume and warns when the FAT partition is much
  smaller than the card
- Saved trails on the card: every Save is a new file, Load opens a list
  with load (framed on the map), GPX export and delete
- Diagnostics: GPS data rows, last start reason, last crash summary
- Messages restored before the clock is set show their date instead of 0s

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

variants/sim/build_wasm.sh

@@ -184,7 +184,7 @@ if [ "$SIM_UI" = "lvgl" ]; then
   done
   # The L2's PSRAM-sized limits (solo/wio-tracker-l2/platformio.ini).
   DEFINES=("${kept[@]}" -DDISPLAY_CLASS=SimLcdDisplay -DMAX_GROUP_CHANNELS=40 -DUI_ZOOM=1 -DLV_CONF_INCLUDE_SIMPLE
-           -DTRAIL_CAPACITY=4096 -DWAYPOINT_CAPACITY=64 -DHIST_CH_MAX=256 -DHIST_DM_MAX=128 -DNEARBY_MAX=64)
+           -DTRAIL_CAPACITY=4096 -DWAYPOINT_CAPACITY=64 -DHIST_CH_MAX=256 -DHIST_DM_MAX=128 -DNEARBY_MAX=64 -DHIST_ARCHIVE)
   INCLUDES+=("-I$LVGL_DIR")
   LINK_EXTRA=(-sFETCH=1)   # map downloads (LvglPort.h) go through emscripten_fetch
 fi

variants/wio-tracker-l2/target.h

@@ -18,6 +18,7 @@ extern WioTrackerL2Board board;
 extern WRAPPER_CLASS radio_driver;
 extern AutoDiscoverRTCClock rtc_clock;
 extern EnvironmentSensorManager sensors;
+extern MicroNMEALocationProvider gps;
 
 #ifdef DISPLAY_CLASS
   extern DISPLAY_CLASS display;