Persist talk opinions and pick topics by weight.

A finished circle never set Tick's peopleChanged bit, so people.json kept pre-talk numbers until morning drift. PickTopic compared a 0..total roll to a 0..1 cursor, so gossip almost never changed the subject.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/HSchool.People.Tests/OpinionGeneratorTests.cs

@@ -52,4 +52,44 @@ public class OpinionGeneratorTests
         Assert.True(child.Opinions.TryGetValue(parentId, out var childView));
         Assert.NotEqual(parentView, childView);
     }
+
+    [Fact]
+    public void RosterJson_RoundTripsFamilyOpinions()
+    {
+        var roster = Fixtures.Generate(Fixtures.Classrooms(4));
+        var child = roster.People.First(person => person.IsStudent && !person.IsParent);
+        var parentId = roster.Families.Single(row => row.Id.Equals(child.FamilyId, StringComparison.Ordinal)).ParentIds[0];
+        Assert.True(child.Opinions.TryGetValue(parentId, out var before));
+
+        var loaded = RosterJson.Parse(RosterJson.Serialize(RosterDocument.From(1, roster))).ToRoster();
+        var loadedChild = loaded.People.First(person => person.Id.Equals(child.Id, StringComparison.Ordinal));
+        Assert.Equal(before, loadedChild.Opinions[parentId]);
+    }
+
+    [Fact]
+    public void SaveWithoutOpinionsField_SeedsFamilyOnLoad()
+    {
+        var roster = Fixtures.Generate(Fixtures.Classrooms(4));
+        var json = RosterJson.Serialize(RosterDocument.From(1, roster));
+        var node = System.Text.Json.Nodes.JsonNode.Parse(json)!;
+        foreach (var person in node["people"]!.AsArray())
+        {
+            person!.AsObject().Remove("opinions");
+        }
+
+        var stripped = RosterJson.Parse(node.ToJsonString()).ToRoster();
+        Assert.True(OpinionGenerator.NeedsFamilyOpinions(stripped));
+        Assert.All(stripped.People, person => Assert.Empty(person.Opinions));
+
+        var seeded = OpinionGenerator.SeedFamily(Fixtures.Catalog(), stripped);
+        Assert.False(OpinionGenerator.NeedsFamilyOpinions(seeded));
+        var child = seeded.People.First(person => person.IsStudent && !person.IsParent);
+        var family = seeded.Families.Single(row => row.Id.Equals(child.FamilyId, StringComparison.Ordinal));
+        Assert.NotEmpty(family.ParentIds);
+        foreach (var parentId in family.ParentIds)
+        {
+            Assert.True(child.Opinions.TryGetValue(parentId, out var toParent));
+            Assert.True(toParent > 0);
+        }
+    }
 }