Add sleep tracking, statistics module and backup features

Features:
- Sleep tracking with timer and manual duration input
- Statistics module with 5 tabs (daily summary, feeding, diapers, sleep, growth)
- Export/Import backup functionality in settings
- Complete German, French and Italian translations

app/src/main/java/it/danieleverducci/lunatracker/fragments/GrowthStatsFragment.kt

@@ -0,0 +1,139 @@
+package it.danieleverducci.lunatracker.fragments
+
+import android.os.Bundle
+import android.view.Gravity
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.LinearLayout
+import android.widget.TextView
+import androidx.fragment.app.Fragment
+import it.danieleverducci.lunatracker.R
+import it.danieleverducci.lunatracker.StatisticsActivity
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+
+class GrowthStatsFragment : Fragment() {
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        return inflater.inflate(R.layout.fragment_growth_stats, container, false)
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        updateUI(view)
+    }
+
+    private fun updateUI(view: View) {
+        val activity = activity as? StatisticsActivity ?: return
+        val calculator = activity.getCalculator()
+
+        val weightHistory = calculator.getWeightHistory()
+        val noDataMessage = view.findViewById<TextView>(R.id.no_data_message)
+
+        if (weightHistory.isEmpty()) {
+            noDataMessage.visibility = View.VISIBLE
+            view.findViewById<View>(R.id.chart_container).visibility = View.GONE
+            view.findViewById<View>(R.id.chart_labels).visibility = View.GONE
+            view.findViewById<TextView>(R.id.current_weight).visibility = View.GONE
+            view.findViewById<TextView>(R.id.weight_gain_week).visibility = View.GONE
+            view.findViewById<TextView>(R.id.weight_gain_month).visibility = View.GONE
+            return
+        }
+
+        noDataMessage.visibility = View.GONE
+
+        // Draw weight chart (line chart approximated with bars)
+        val chartContainer = view.findViewById<LinearLayout>(R.id.chart_container)
+        val chartLabels = view.findViewById<LinearLayout>(R.id.chart_labels)
+        chartContainer.removeAllViews()
+        chartLabels.removeAllViews()
+
+        val recentWeights = weightHistory.takeLast(10) // Show last 10 measurements
+        val minWeight = recentWeights.minOfOrNull { it.weightGrams } ?: 0
+        val maxWeight = recentWeights.maxOfOrNull { it.weightGrams } ?: 1
+        val weightRange = (maxWeight - minWeight).coerceAtLeast(100) // At least 100g range
+        val dateFormat = SimpleDateFormat("d/M", Locale.getDefault())
+
+        for (point in recentWeights) {
+            // Bar container
+            val barContainer = LinearLayout(requireContext()).apply {
+                layoutParams = LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.MATCH_PARENT, 1f)
+                orientation = LinearLayout.VERTICAL
+                gravity = Gravity.BOTTOM or Gravity.CENTER_HORIZONTAL
+                setPadding(4, 0, 4, 0)
+            }
+
+            // Calculate relative height (showing weight above minimum)
+            val relativeWeight = point.weightGrams - minWeight + (weightRange * 0.1).toInt()
+            val barHeight = (relativeWeight.toFloat() / (weightRange * 1.2) * 100).toInt()
+
+            val bar = View(requireContext()).apply {
+                layoutParams = LinearLayout.LayoutParams(
+                    LinearLayout.LayoutParams.MATCH_PARENT,
+                    (barHeight * resources.displayMetrics.density).toInt()
+                )
+                setBackgroundColor(resources.getColor(R.color.accent, null))
+            }
+            barContainer.addView(bar)
+
+            // Weight value on top
+            val weightLabel = TextView(requireContext()).apply {
+                layoutParams = LinearLayout.LayoutParams(
+                    LinearLayout.LayoutParams.WRAP_CONTENT,
+                    LinearLayout.LayoutParams.WRAP_CONTENT
+                )
+                val kg = point.weightGrams / 1000f
+                text = String.format(Locale.getDefault(), "%.1f", kg)
+                textSize = 8f
+                gravity = Gravity.CENTER
+            }
+            barContainer.addView(weightLabel, 0)
+
+            chartContainer.addView(barContainer)
+
+            // Date label
+            val label = TextView(requireContext()).apply {
+                layoutParams = LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WRAP_CONTENT, 1f)
+                text = dateFormat.format(Date(point.time * 1000))
+                textSize = 10f
+                gravity = Gravity.CENTER
+            }
+            chartLabels.addView(label)
+        }
+
+        // Current weight
+        val currentWeight = weightHistory.lastOrNull()
+        if (currentWeight != null) {
+            val kg = currentWeight.weightGrams / 1000f
+            view.findViewById<TextView>(R.id.current_weight).text =
+                getString(R.string.stats_current_weight, String.format(Locale.getDefault(), "%.2f kg", kg))
+        }
+
+        // Weight gain calculations
+        val gainWeek = calculator.getWeightGainForDays(7)
+        val gainMonth = calculator.getWeightGainForDays(30)
+
+        val weekView = view.findViewById<TextView>(R.id.weight_gain_week)
+        val monthView = view.findViewById<TextView>(R.id.weight_gain_month)
+
+        if (gainWeek != null) {
+            weekView.text = getString(R.string.stats_weight_gain_week, gainWeek)
+            weekView.visibility = View.VISIBLE
+        } else {
+            weekView.visibility = View.GONE
+        }
+
+        if (gainMonth != null) {
+            monthView.text = getString(R.string.stats_weight_gain_month, gainMonth)
+            monthView.visibility = View.VISIBLE
+        } else {
+            monthView.visibility = View.GONE
+        }
+    }
+}