feat(todo): the server on halkyon_base

Todo's server includes halkyon_base (ADR 0014), configured for Todo:
its basics say it serves `todo`, sign-in mails name Halkyon Todo, the
source is this repository, minimumAppBuild 1. Authentication through
the module (anonymous, GitHub, email codes, server-side sessions) in
place of the scaffold's email-and-password provider; the module's
pruning scheduled once however often the server starts. The scaffold's
greeting, its Flutter web hosting, cloud storage and Docker files go;
session logs are never persisted. Todo was never deployed, so its
migrations start again with one initial migration. The root's lints
apply, with the four constructor rules off as on Learn's server.

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/pubspec.yaml

@@ -1,7 +1,6 @@
 name: halkyon_todo_server
-description: Starting point for a Serverpod server.
-# version: 1.0.0
-# homepage: https://www.example.com
+description: Halkyon Todo's server.
+publish_to: none
 
 environment:
   sdk: '^3.13.0'
@@ -9,34 +8,20 @@ environment:
 resolution: workspace
 
 dependencies:
+  clock: ^1.1.3
+  # What every Halkyon server has (ADR 0014): signing in, the account and its
+  # deletion, pruning, the instance's basics. A Serverpod module among the
+  # repository's shared packages.
+  halkyon_base_server:
+    path: ../../../packages/halkyon_base_server
   serverpod: 4.0.4
   serverpod_auth_idp_server: 4.0.4
-  serverpod_cloud_storage: 4.0.4
 
 dev_dependencies:
-  lints: '>=3.0.0 <7.0.0'
   serverpod_test: 4.0.4
   test: ^1.25.5
 
 serverpod:
-  scripts:
-    # Build the Flutter web app and copy it to the server's web directory.
-    # Windows uses xcopy since flutter's --output flag doesn't work there.
-    # See: https://github.com/flutter/flutter/issues/157886
-    # On failure, clean and retry once to clear stale Flutter build caches.
-    flutter_build:
-      windows: >-
-        (if exist web\app rmdir /S /Q web\app)
-        & cd /D ..\halkyon_todo_flutter
-        & set ARGS=web --base-href /
-        && (call flutter build %ARGS% || (flutter clean && call flutter build %ARGS%))
-        && xcopy /E /I /Y build\web ..\halkyon_todo_server\web\app
-      posix: |
-        rm -rf ../halkyon_todo_server/web/app
-        cd ../halkyon_todo_flutter
-        set -- web --base-href / --output ../halkyon_todo_server/web/app
-        flutter build "$@" || { flutter clean && flutter build "$@"; }
-
   # Companion Flutter apps that `serverpod start` can launch (Ctrl+R), keyed
   # by a display alias. The default device is the web server, opening the
   # machine's default browser when ready. All non-reserved properties are
@@ -59,6 +44,6 @@ serverpod:
   flutter_apps:
     halkyon_todo:
       path: ../halkyon_todo_flutter
-      displayName: "Halkyon todo app"
+      displayName: "Halkyon Todo"
       auto_launch: true
       target: lib/driver.dart