Add jump rope FIT session metrics: total_cycles, avg_cadence, max_cadence

Adds standard FIT fields for jump rope activities in the session message:
- SetTotalCycles() - total jump count as cycles
- SetAvgCadence() - average jump rate (calculated from session data)
- SetMaxCadence() - maximum jump rate (calculated from session data)

https://claude.ai/code/session_0153U2Nv6Vuqfzh2w1w4b4tc

Author: claude

src/qfit.cpp

@@ -162,6 +162,11 @@ void qfit::save(const QString &filename, QList<SessionLine> session, BLUETOOTH_T
     double watt_sum = 0;
     int watt_count = 0;
 
+    // Variables for jump rope cadence
+    double cadence_sum = 0;
+    int cadence_count = 0;
+    uint8_t max_cadence = 0;
+
     for (int i = firstRealIndex; i < session.length(); i++) {
         if (session.at(i).coordinate.isValid()) {
             gps_data = true;
@@ -204,6 +209,15 @@ void qfit::save(const QString &filename, QList<SessionLine> session, BLUETOOTH_T
             watt_sum += session.at(i).watt;
             watt_count++;
         }
+
+        // Collect cadence data for jump rope
+        if (type == JUMPROPE && session.at(i).cadence > 0) {
+            cadence_sum += session.at(i).cadence;
+            cadence_count++;
+            if (session.at(i).cadence > max_cadence) {
+                max_cadence = session.at(i).cadence;
+            }
+        }
     }
 
     if (speed_count > 0) {
@@ -448,6 +462,15 @@ void qfit::save(const QString &filename, QList<SessionLine> session, BLUETOOTH_T
         sessionMesg.SetSubSport(FIT_SUB_SPORT_GENERIC);
         if (session.last().stepCount)
             sessionMesg.SetJumpCount(session.last().stepCount);
+        // Total cycles
+        if (session.last().stepCount)
+            sessionMesg.SetTotalCycles(session.last().stepCount);
+        // Avg cadence (jump rate)
+        if (cadence_count > 0)
+            sessionMesg.SetAvgCadence((uint8_t)(cadence_sum / cadence_count));
+        // Max cadence (max jump rate)
+        if (max_cadence > 0)
+            sessionMesg.SetMaxCadence(max_cadence);
     } else {
 
         sessionMesg.SetSport(FIT_SPORT_CYCLING);