Fix edit sheet bottom time to use computed value and write override

The edit sheet's Bottom Time field was initialized from the raw DB column
(which held total runtime for imported dives) and wrote to bottomTimeSec
which stats computation ignores. Now:
- Initializes from computed stats when available (e.g. 27 min, not 73)
- When changed, writes to bottomEndTOverrideSec so the override flows
  through stats recomputation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: shaheinm

Profundum/Profundum/Views/DiveDetailView.swift

@@ -214,7 +214,8 @@ struct DiveDetailView: View {
                 editingDive: dive,
                 editingTags: tags,
                 editingTeammateIds: loadedTeammateIds,
-                editingEquipmentIds: loadedEquipmentIds
+                editingEquipmentIds: loadedEquipmentIds,
+                computedBottomTimeSec: stats?.bottomTimeSec
             )
         }
         .alert("Error", isPresented: Binding(get: { errorMessage != nil }, set: { if !$0 { errorMessage = nil } })) {

Profundum/Profundum/Views/NewDiveSheet.swift

@@ -13,6 +13,7 @@ struct NewDiveSheet: View {
     @State private var maxDepthText = "30.0"
     @State private var avgDepthText = "18.0"
     @State private var bottomTimeMinutes = 50
+    @State private var initialBottomTimeMinutes = 50
 
     @State private var isCCR = false
     @State private var decoRequired = false
@@ -53,6 +54,7 @@ struct NewDiveSheet: View {
     var editingTags: [String] = []
     var editingTeammateIds: [String] = []
     var editingEquipmentIds: [String] = []
+    var computedBottomTimeSec: Int32?
 
     private var sheetTitle: String {
         editingDive != nil ? "Edit Dive" : "New Dive"
@@ -122,7 +124,8 @@ struct NewDiveSheet: View {
                     let displayAvgDepth = UnitFormatter.depth(dive.avgDepthM, unit: appState.depthUnit)
                     maxDepthText = String(format: "%.1f", displayMaxDepth)
                     avgDepthText = String(format: "%.1f", displayAvgDepth)
-                    bottomTimeMinutes = Int(dive.bottomTimeSec / 60)
+                    bottomTimeMinutes = Int((computedBottomTimeSec ?? dive.bottomTimeSec) / 60)
+                    initialBottomTimeMinutes = bottomTimeMinutes
                     isCCR = dive.isCcr
                     decoRequired = dive.decoRequired
                     cnsPercentText = String(format: "%.0f", dive.cnsPercent)
@@ -700,7 +703,9 @@ struct NewDiveSheet: View {
             computerDiveNumber: editingDive?.computerDiveNumber,
             fingerprint: editingDive?.fingerprint,
             timezoneOffsetSec: savedTimezoneOffset,
-            bottomEndTOverrideSec: editingDive?.bottomEndTOverrideSec
+            bottomEndTOverrideSec: bottomTimeMinutes != initialBottomTimeMinutes
+                ? Int32(bottomTimeMinutes * 60)
+                : editingDive?.bottomEndTOverrideSec
         )
 
         var allTags = [selectedDiveTypeTag.rawValue]