Add password hashing, user settings with 2FA, and project image lightbox.

Hardens auth with PBKDF2, lockouts, local QR setup, and safer embeds while moving account security under the username menu.

database/add-2fa.sql

@@ -0,0 +1,8 @@
+IF COL_LENGTH('dbo.admins', 'two_factor_enabled') IS NULL
+BEGIN
+    ALTER TABLE dbo.admins ADD two_factor_enabled BIT NOT NULL CONSTRAINT DF_admins_two_factor_enabled DEFAULT(0);
+END
+IF COL_LENGTH('dbo.admins', 'two_factor_secret') IS NULL
+BEGIN
+    ALTER TABLE dbo.admins ADD two_factor_secret NVARCHAR(64) NULL;
+END