feat(02-02): wire deleteLog through App.jsx and WorkoutPage to ExerciseCard

- Added deleteLog function in App.jsx: calls DELETE /api/logs and removes entry from local logs state
- Passed onDeleteSet={deleteLog} to WorkoutPage in workout view render
- Updated WorkoutPage function signature to accept onDeleteSet prop
- Passed onDeleteSet through to each ExerciseCard (ExerciseCard already calls it in handleDeleteSet)
- Non-logged sets (404 from backend) silently ignored via catch block

frontend/src/App.jsx

@@ -90,6 +90,28 @@ function App() {
     }
   }
 
+  const deleteLog = async (programExerciseId, setNumber) => {
+    try {
+      await fetch(`${API_URL}/logs`, {
+        method: 'DELETE',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          user_id: userId,
+          program_exercise_id: programExerciseId,
+          date: today,
+          set_number: setNumber
+        })
+      })
+      // Remove from local logs state
+      setLogs(prev => ({
+        ...prev,
+        [programExerciseId]: (prev[programExerciseId] || []).filter(l => l.set_number !== setNumber)
+      }))
+    } catch (err) {
+      console.error('Failed to delete log:', err)
+    }
+  }
+
   const startWorkout = async (day) => {
     await fetchProgram() // Ensure program is loaded
     setSelectedDay(day)
@@ -135,6 +157,7 @@ function App() {
         week={currentWeek}
         logs={logs}
         onLogSet={logSet}
+        onDeleteSet={deleteLog}
         onBack={() => setView('dashboard')}
         fetchProgression={fetchProgression}
       />