refactor(base): SimpleLogin's forwarding page on the OpenID Connect module (ADR 0023)

halkyon_base depends on halkyon_oidc_server, and its forwarding page
is now the module's (`addOidcCallbackForwarding`) with Halkyon's table
of apps and its page in English or German; its tests keep what is
Halkyon's own, the rest is tested in the module.

Every host now includes the module: migrations `…-oidc-module` in
halkyon_base, Learn and Todo create its two tables (no data touched)
and record its version; Learn's devices get them empty, as they have
halkyon_base's server-only tables. halkyon_base_client depends on
halkyon_oidc_client, whose models its generated code uses, and Learn's
server image copies both packages into its narrowed workspace.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/todo/halkyon_todo_server/migrations/20261023181810436-oidc-module/definition_project.json

@@ -0,0 +1,34 @@
+{
+  "__className__": "serverpod.DatabaseDefinition",
+  "schemaVersion": 2,
+  "moduleName": "halkyon_todo",
+  "tables": [],
+  "installedModules": [
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "halkyon_base",
+      "version": "20261023181809816-oidc-module"
+    },
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "serverpod",
+      "version": "20260824182259319"
+    },
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "serverpod_auth_idp",
+      "version": "20260924105404509"
+    },
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "halkyon_oidc",
+      "version": "20261023180644988"
+    },
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "serverpod_auth_core",
+      "version": "20260924105232991"
+    }
+  ],
+  "migrationApiVersion": 1
+}