refactor: change node count variables from uint8_t to uint16_t (#8478)

This is a non-breaking change that increases the internal representation
of node counts from uint8_t (max 255) to uint16_t (max 65535) to support
larger mesh networks, particularly on ESP32-S3 devices with PSRAM.

Changes:
- NodeStatus: numOnline, numTotal, lastNumTotal (uint8_t -> uint16_t)
- ProtobufModule: numOnlineNodes (uint8_t -> uint16_t)
- MapApplet: loop counters changed to size_t for consistency with getNumMeshNodes()
- NodeStatus: Fixed log format to use %u for unsigned integers

Note: Default class methods keep uint32_t for numOnlineNodes parameter
to match the public API and allow flexibility, even though internal node
counts use uint16_t (max 65535 nodes).

This change does NOT affect protobuf definitions, maintaining wire
compatibility with existing clients and devices.

src/mesh/Default.h

@@ -46,12 +46,15 @@ class Default
     static uint32_t getConfiguredOrDefaultMs(uint32_t configuredInterval);
     static uint32_t getConfiguredOrDefaultMs(uint32_t configuredInterval, uint32_t defaultInterval);
     static uint32_t getConfiguredOrDefault(uint32_t configured, uint32_t defaultValue);
+    // Note: numOnlineNodes uses uint32_t to match the public API and allow flexibility,
+    // even though internal node counts use uint16_t (max 65535 nodes)
     static uint32_t getConfiguredOrDefaultMsScaled(uint32_t configured, uint32_t defaultValue, uint32_t numOnlineNodes);
     static uint8_t getConfiguredOrDefaultHopLimit(uint8_t configured);
     static uint32_t getConfiguredOrMinimumValue(uint32_t configured, uint32_t minValue);
 
   private:
-    static float congestionScalingCoefficient(int numOnlineNodes)
+    // Note: Kept as uint32_t to match the public API parameter type
+    static float congestionScalingCoefficient(uint32_t numOnlineNodes)
     {
         // Increase frequency of broadcasts for small networks regardless of preset
         if (numOnlineNodes <= 10) {

src/mesh/ProtobufModule.h

@@ -13,7 +13,7 @@ template <class T> class ProtobufModule : protected SinglePortModule
     const pb_msgdesc_t *fields;
 
   public:
-    uint8_t numOnlineNodes = 0;
+    uint16_t numOnlineNodes = 0;
     /** Constructor
      * name is for debugging output
      */