fix(turns): align info.TaskEnvironmentID with the resolved env after fallback

GetWorkspaceInfoForSession initializes info.TaskEnvironmentID from
session.TaskEnvironmentID, then resolves the env — first by that ID,
falling back to GetTaskEnvironmentByTaskID when the session's ID
points to a stale/missing row. When the fallback kicks in, the
resolved env has a different ID, but applyTaskEnvironmentToWorkspaceInfo
was only updating info.TaskEnvironmentID when it was empty. So
downstream reconcilers received metadata + path from one env keyed by
a different env's ID.

Always overwrite info.TaskEnvironmentID with env.ID inside the apply
function — once we've picked an env to spread, the info should
identify that env consistently.

apps/backend/internal/task/service/service_turns.go

@@ -395,9 +395,14 @@ func (s *Service) GetWorkspaceInfoForSession(ctx context.Context, taskID, sessio
 }
 
 func applyTaskEnvironmentToWorkspaceInfo(info *lifecycle.WorkspaceInfo, env *models.TaskEnvironment) {
-	if info.TaskEnvironmentID == "" {
-		info.TaskEnvironmentID = env.ID
-	}
+	// Always align info.TaskEnvironmentID with the env we resolved against.
+	// When session.TaskEnvironmentID points to a stale/missing env, the
+	// caller falls back to GetTaskEnvironmentByTaskID and ends up with a
+	// different env.ID. Previously we only updated info.TaskEnvironmentID
+	// when it was empty, so the metadata + path here would come from env
+	// while the ID still pointed at the stale row — a mismatch downstream
+	// reconcilers and progress events would key off the wrong env.
+	info.TaskEnvironmentID = env.ID
 	if info.WorkspacePath == "" {
 		info.WorkspacePath = env.WorkspacePath
 	}