Lora region preset map (#10736)

* Added lora region and preset maps

* Protos

* Address PR review feedback

- Log (and break/skip) when the region preset map exceeds its array bounds
  instead of silently dropping regions
- Derive test bounds from the generated nanopb array sizes via sizeof()
  instead of hard-coded magic numbers
- Fix want_config sequence comment (missing comma, STATE_SEND_MODULECONFIG)
- Specify a language on the spec's fenced code blocks (markdownlint MD040)

* Fix want_config stall: handle STATE_SEND_REGION_PRESETS in PhoneAPI::available()

available() had a separate per-state switch that wasn't updated for the new
state, so it returned false ('unexpected state 5') and getFromRadio() was
never called - the config handshake stalled after metadata and the client
timed out. Verified via the native simulator integration test.

src/mesh/PhoneAPI.cpp

@@ -12,6 +12,7 @@
 #include "Channels.h"
 #include "Default.h"
 #include "FSCommon.h"
+#include "MeshRadio.h"
 #include "MeshService.h"
 #include "NodeDB.h"
 #include "PacketHistory.h"
@@ -516,9 +517,10 @@ bool PhoneAPI::handleToRadio(const uint8_t *buf, size_t bufLength)
     STATE_SEND_UIDATA,
     STATE_SEND_OWN_NODEINFO,
     STATE_SEND_METADATA,
-    STATE_SEND_CHANNELS
+    STATE_SEND_REGION_PRESETS, // region -> valid modem presets (one message)
+    STATE_SEND_CHANNELS,
     STATE_SEND_CONFIG,
-    STATE_SEND_MODULE_CONFIG,
+    STATE_SEND_MODULECONFIG,
     STATE_SEND_OTHER_NODEINFOS, // states progress in this order as the device sends to the client
     STATE_SEND_FILEMANIFEST,
     STATE_SEND_COMPLETE_ID,
@@ -636,7 +638,20 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
             memset(&fromRadioScratch.metadata, 0, sizeof(fromRadioScratch.metadata));
         }
 #endif
+        state = STATE_SEND_REGION_PRESETS;
+        break;
+
+    case STATE_SEND_REGION_PRESETS:
+        // Tell the client which modem presets are legal in each region so its UI
+        // can block illegal region+preset combinations. This is public RF /
+        // regulatory information (region and modem_preset are already in the
+        // unauthenticated LoRa whitelist below), so it is sent unconditionally —
+        // even an unauthorized/locked-down client can render a correct picker.
+        LOG_DEBUG("Send region preset map");
+        fromRadioScratch.which_payload_variant = meshtastic_FromRadio_region_presets_tag;
+        getRegionPresetMap(fromRadioScratch.region_presets);
         state = STATE_SEND_CHANNELS;
+        config_state = 0; // STATE_SEND_CHANNELS indexes channels starting at 0
         break;
 
     case STATE_SEND_CHANNELS:
@@ -1517,6 +1532,7 @@ bool PhoneAPI::available()
     case STATE_SEND_CONFIG:
     case STATE_SEND_MODULECONFIG:
     case STATE_SEND_METADATA:
+    case STATE_SEND_REGION_PRESETS:
     case STATE_SEND_OWN_NODEINFO:
     case STATE_SEND_FILEMANIFEST:
     case STATE_SEND_COMPLETE_ID: