Server: start a retried write transaction from the database, not from the attempt that failed

tests/DodoSSH.Api.Tests/TeamEndpointTests.cs

@@ -647,6 +647,38 @@ public sealed class TeamEndpointTests(ApiFixture fixture)
             .Role.ShouldBe(TeamMemberRole.Owner);
     }
 
+    /// <remarks>
+    /// The commit lost on its way to the database, which the execution strategy answers by running the
+    /// transaction again on the same context. That context still held the two memberships as the failed
+    /// attempt left them — already owner, already admin, and marked unchanged — so the retry saved nothing,
+    /// committed, and answered 204 over a team whose roles had not moved. See <c>FreshAttempts</c>.
+    /// </remarks>
+    [Fact]
+    public async Task ATransferWhoseCommitIsLost_IsRetriedFromTheDatabase_AndStillLands()
+    {
+        var owner = await EnrolledClientAsync("retry-owner", "rowner@example.com");
+        await EnrolledClientAsync("retry-successor", "rsuccessor@example.com");
+
+        var team = await CreateTeamAsync(owner, "Retried handover");
+        var entry = await LookupAsync(owner, "rsuccessor@example.com");
+
+        await AddMemberAsync(owner, team.TeamId, entry.UserId, TeamMemberRole.Member);
+
+        var failedBefore = fixture.Commits.Failed;
+        fixture.Commits.FailNextCommit();
+
+        var response = await owner.PostContractAsync(
+            OwnerUrl(team.TeamId), new TransferTeamOwnershipRequest(entry.UserId));
+
+        response.StatusCode.ShouldBe(HttpStatusCode.NoContent);
+        fixture.Commits.Failed.ShouldBe(failedBefore + 1, "the first commit has to have been lost for this to mean anything");
+
+        var members = await ReadAsync<IReadOnlyList<TeamMemberSummary>>(owner, MembersUrl(team.TeamId));
+
+        members.Where(row => row.UserId == entry.UserId).ShouldHaveSingleItem().Role.ShouldBe(TeamMemberRole.Owner);
+        members.Count(row => row.Role == TeamMemberRole.Owner).ShouldBe(1);
+    }
+
     /// <remarks>
     /// The thing that was impossible before this endpoint existed. An owner could not be removed and
     /// could not be demoted, so somebody who left the company owning a team left it owned by them for