feat(server): record set releases and the nests they made

Releasing a drawing set makes one nest per material group, so a kit run
spans several nests. The server now records which set revision was
released, the multiplier and the nests it made, so a run can be tracked
across its nests and a nest can say where it came from.

The client uploads every nest first and posts the release last: a failure
part-way leaves ordinary nests and no release, never a release pointing at
missing nests. For the same reason a release is accepted for an older set
revision or an archived set, since the nests already exist by then. The
release id is client-allocated and a nest belongs to at most one release,
so a retried post gets 409 with the release that already holds it.

Releases are append-only and read joined to each nest's current metadata,
so status and deletion are always current. The tables join schema v7, as
the set tables have not shipped yet.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

OpenNest.Server.Tests/DrawingSetDatabaseTests.cs

@@ -43,7 +43,7 @@ public sealed class DrawingSetDatabaseTests
         Assert.Throws<SqliteException>(() => new NestDatabase(factory.DatabasePath, pooling: false));
 
         Assert.Equal(6L, Scalar(factory.DatabasePath, "PRAGMA user_version"));
-        Assert.Equal(0L, Scalar(factory.DatabasePath, "SELECT COUNT(*) FROM sqlite_master WHERE name LIKE 'drawing_set%'"));
+        Assert.Equal(0L, Scalar(factory.DatabasePath, "SELECT COUNT(*) FROM sqlite_master WHERE name LIKE 'drawing_set%' OR name LIKE 'set_release%'"));
         Assert.Equal(before, Digest(factory.DatabasePath));
         Execute(factory.DatabasePath, "DROP TABLE ix_drawing_set_members_drawing");
         using var database = new NestDatabase(factory.DatabasePath, pooling: false);
@@ -295,7 +295,7 @@ public sealed class DrawingSetDatabaseTests
     }
 
     /// <summary>
-    /// A real schema-v6 file with nests and a library drawing: the set tables are additive,
+    /// A real schema-v6 file with nests and a library drawing: the set and release tables are additive,
     /// so dropping them restores v6 exactly. Returns the drawing's id.
     /// </summary>
     private static Guid CreateVersion6Database(string path)
@@ -314,7 +314,10 @@ public sealed class DrawingSetDatabaseTests
             database.UpdateDrawing(drawing, edit, null, 1);
         }
 
-        Execute(path, "DROP TABLE drawing_set_members; DROP TABLE drawing_sets; DROP TABLE drawing_set_revisions; PRAGMA user_version=6;");
+        Execute(path, """
+            DROP TABLE set_release_nests; DROP TABLE set_releases;
+            DROP TABLE drawing_set_members; DROP TABLE drawing_sets; DROP TABLE drawing_set_revisions; PRAGMA user_version=6;
+            """);
         return drawing;
     }