refactor(net): unique_ptr for connection-lifecycle objects (#11459)

- WiFiServerAPI/ethServerAPI apiPort and ethApiServer's listener are
  create/destroy cycles that repeat across WiFi teardown and W5500
  chip resets; the manual delete+null bookkeeping becomes reset().
  (ethTlsApiServer's listener is left for a follow-up: that file is
  already touched by the partial-init fix PR and converting it here
  would conflict.)

- ContentHandler::handleFormUpload held its body parser raw with
  delete on four separate exit paths of a per-request handler; any
  future early return was a silent leak. unique_ptr removes all four.

- The portduino ch341Hal global becomes unique_ptr. The LoRa-error
  recovery loop's delete/null/new sequence was correct only by
  hand-preserved ordering; it becomes reset()/make_unique. RadioLibHAL
  keeps a non-owning raw pointer, as before.

No behavior change.

src/mesh/RadioInterface.cpp

@@ -414,7 +414,7 @@ std::unique_ptr<RadioInterface> initLoRa()
     LOG_DEBUG("Activate %s radio on SPI port %s", portduino_config.loraModules[portduino_config.lora_module].c_str(),
               portduino_config.lora_spi_dev.c_str());
     if (portduino_config.lora_spi_dev == "ch341") {
-        RadioLibHAL = ch341Hal;
+        RadioLibHAL = ch341Hal.get(); // non-owning: the ch341 HAL stays owned by the global unique_ptr
     } else {
         if (RadioLibHAL != nullptr) {
             delete RadioLibHAL;