feat(ota): add partition-table signature handling for OTA updates

Implemented functionality to generate and compare partition-table
signatures during OTA updates. This enhancement ensures that the
target build's partition layout matches the device's actual layout,
improving the reliability of OTA updates and preventing issues
related to partition changes.

examples/simple_repeater/main.cpp

@@ -82,6 +82,11 @@ void setup() {
     store.save("_main", the_mesh.self_id);
   }
 
+  // Print the running firmware version at boot so it's visible after an OTA
+  // reboot without having to issue `ver` manually.
+  Serial.print("Firmware: "); Serial.print(FIRMWARE_VERSION);
+  Serial.print(" (built "); Serial.print(FIRMWARE_BUILD_DATE); Serial.println(")");
+
   Serial.print("Repeater ID: ");
   mesh::Utils::printHex(Serial, the_mesh.self_id.pub_key, PUB_KEY_SIZE); Serial.println();