fix(macdive): emit sample tank pressure via allTankPressures key

MacDive XML parser wrote profile sample pressure as point['pressure'],
but UddfEntityImporter._storeTankPressures reads it exclusively from
point['allTankPressures'] (a list of {pressure, tankIndex} maps) — the
convention shared by Subsurface, Shearwater, UDDF, and CSV parsers. The
singular `pressure` key was silently dropped, so every MacDive XML
import landed with zero rows in tank_pressure and the cylinder pressure
trace missing from the profile chart.

Invisible to the synthetic parser test (only asserted timestamp), so it
slipped through review. New regression guards in both the synthetic and
real-sample suites now exercise the path end-to-end.

Author: ericgriffin

lib/features/universal_import/data/parsers/macdive_xml_parser.dart

@@ -280,7 +280,16 @@ class MacDiveXmlParser implements ImportParser {
     for (final s in d.samples) {
       final point = <String, dynamic>{'timestamp': s.time.inSeconds};
       if (s.depthMeters != null) point['depth'] = s.depthMeters;
-      if (s.pressureBar != null) point['pressure'] = s.pressureBar;
+      if (s.pressureBar != null) {
+        // UddfEntityImporter._storeTankPressures reads sample pressure
+        // exclusively from `allTankPressures` (a list of
+        // {pressure, tankIndex} maps); the singular `pressure` key it
+        // ignores. MacDive XML emits one <pressure> per sample for the
+        // primary tank, so map to tankIndex 0 to match Subsurface/UDDF/CSV.
+        point['allTankPressures'] = [
+          <String, dynamic>{'pressure': s.pressureBar, 'tankIndex': 0},
+        ];
+      }
       if (s.temperatureCelsius != null) {
         point['temperature'] = s.temperatureCelsius;
       }

test/features/universal_import/data/parsers/macdive_xml_parser_test.dart

@@ -101,6 +101,30 @@ void main() {
       expect((profile[1] as Map)['timestamp'], 60);
     });
 
+    test('profile sample pressure exposed via allTankPressures', () async {
+      // UddfEntityImporter._storeTankPressures only reads the
+      // `allTankPressures` key on each profile point (a list of
+      // {pressure, tankIndex} maps). Writing the legacy `pressure` key
+      // silently drops the cylinder pressure trace from the profile chart.
+      // MacDive XML emits one <pressure> per sample for the primary tank,
+      // so we map it to tankIndex 0.
+      final payload = await const MacDiveXmlParser().parse(bytes);
+      final dive = payload.entitiesOf(ImportEntityType.dives).first;
+      final profile = (dive['profile'] as List).cast<Map<String, dynamic>>();
+
+      final firstSample = profile[0];
+      final allTP = firstSample['allTankPressures'] as List?;
+      expect(
+        allTP,
+        isNotNull,
+        reason: 'importer reads sample pressure from allTankPressures only',
+      );
+      expect(allTP!.length, 1, reason: 'single-gas dive has one tank entry');
+      final tp0 = allTP.first as Map<String, dynamic>;
+      expect(tp0['tankIndex'], 0);
+      expect(tp0['pressure'], 200);
+    });
+
     test('dive links gear via equipmentRefs with matching uddfId', () async {
       final payload = await const MacDiveXmlParser().parse(bytes);
       final dive = payload.entitiesOf(ImportEntityType.dives).first;

test/features/universal_import/data/parsers/macdive_xml_real_sample_test.dart

@@ -134,6 +134,33 @@ void main() {
       expect(withProfile, isNotEmpty);
     });
 
+    test('profile samples carry tank pressure via allTankPressures', () async {
+      // Regression guard: MacDive XML samples emit <pressure> per primary
+      // tank, but the importer reads pressure exclusively from
+      // `allTankPressures` (a list of {pressure, tankIndex} maps). Writing
+      // the singular `pressure` key drops the cylinder pressure trace
+      // entirely — counts would still tally but the profile chart would
+      // not render the cylinder pressure line.
+      if (skipIfNoFixture()) return;
+      final payload = await const MacDiveXmlParser().parse(bytes);
+      final dives = payload.entitiesOf(ImportEntityType.dives);
+      final samplesWithPressure = dives
+          .map((d) => (d['profile'] as List?) ?? const [])
+          .expand((p) => p)
+          .where(
+            (p) =>
+                ((p as Map)['allTankPressures'] as List?)?.isNotEmpty ?? false,
+          );
+      expect(
+        samplesWithPressure,
+        isNotEmpty,
+        reason:
+            'real MacDive exports include <pressure> in samples; if no '
+            'allTankPressures entries appear, the profile chart will be '
+            'missing its cylinder pressure trace',
+      );
+    });
+
     test('profile timestamps span the dive (not all zero)', () async {
       // Regression guard: real MacDive exports format <time> as decimal
       // seconds ("10.00"), which int.tryParse silently rejects. The bug