merge: upstream/dev into webconfig (v1.16.0 base -> 2026-07-19)

First upstream merge since the 2026-06-06 base (191 upstream commits). 14 files
conflicted; resolutions below.

Fleet-critical check (Constraint 1): upstream reordered NodePrefs members
(rx_boosted_gain / path_hash_mode moved to the struct tail) but did NOT change
/com_prefs. Persistence is written field-by-field at explicit offsets, so member
order is in-memory only. Verified the fork's writeCommonPrefsImage() is
byte-identical to upstream's inline writer at every offset (79 pad, 121, 122,
290-294). No migration needed.

Resolutions:
- CommonCLI.h: kept the fork's NodePrefs (superset) and adopted upstream's
  setRxBoostedGain(bool)->bool signature change, which CommonCLI.cpp now uses to
  report unsupported. Corrected a stale comment claiming rx_boosted_gain lives at
  offset 79 (it is a pad; the field is at 290).
- CommonCLI.cpp: kept the fork's legacy /com_prefs migration and the extracted
  writeCommonPrefsImage() call.
- UITask.cpp: three-way merge - upstream's drawTextCentered + powering-off
  screen, plus the fork's WITH_WEBCONFIG portal/reboot screens.
- ESP32Board.cpp, MeshCore.h, platformio.ini: kept both sides (fork OTA additions
  alongside upstream powerOff/enterDeepSleep and Packet.cpp).
- MicroNMEALocationProvider.h: took upstream's claim/release and added the
  _claims member they depend on.
- MyMesh.cpp/.h (repeater + room server): kept the fork's superset defaults.
- Removed duplicate declarations auto-merge produced: RadioLibWrapper::_cad_enabled
  and MyMesh::getCADEnabled().

Verification: native suite 15/15 (incl. upstream's new test_mesh_tables), both
MQTT smoke builds green, ArduinoJson pin check passes. Hardware validation next.

examples/simple_room_server/UITask.cpp

@@ -46,7 +46,8 @@ void UITask::begin(NodePrefs* node_prefs, const char* build_date, const char* fi
   }
 
   // v1.2.3 (1 Jan 2025)
-  sprintf(_version_info, "%s (%s)", version, build_date);
+  snprintf(_version_info, sizeof(_version_info), "%s (%s)", version, build_date);
+  free(version);
 }
 
 void UITask::renderCurrScreen() {