In ndcode_site:

* Move navigation from _menu.json files in each navigation-parent directory to a navigation tree structure in the database, update navbar, menu pages, blog posts
* Fix missing awaits on transaction.commit()
* Make get_session() readonly and throw an exception if session cannot be found rather than trying to create it, make get_account() throw an exception if not signed in, make get_navigation() and the related navbar logic throw useful exceptions if the navigation tree doesn't exist or doesn't the match site pages, make get_nodemailer throw useful exceptions if the nodemailer data doesn't exist
* Finish changing XDate.now() to env.now, new XDate() to new XDate(env.now)

diff --git a/ndcode_site b/ndcode_site
index a4adebc..8a0a622 160000 (submodule)
--- a/ndcode_site
+++ b/ndcode_site
@@ -1 +1 @@
-Subproject commit a4adebcf758195fc268cc4f47a5d914abfab21a7
+Subproject commit 8a0a6220fa7da5248b35af323043fce4c1ff08b0