feat(base): signing in with SimpleLogin through the register (ADR 0020, step 2)

The `simpleLogin` endpoint on halkyon_oidc's SimpleLogin preset: `begin`
for the app and platform (the state's marker for the forwarding page), at
most 30 an hour per network; `complete` with SimpleLogin's code, signed out
a session for the account with that SimpleLogin ID, signed in SimpleLogin
added to the caller's account, who becomes identified and anonymous no
longer. Someone new gets no account yet: their identity waits 30 minutes
under the attempt's ID (D16), with a handle suggested from their name,
`anna_mueller` (D17), for the sign-up of step 3.

The register alone holds the instance's SimpleLogin app
(`simpleLoginClientId`, `simpleLoginClientSecret`) and exchanges codes; a
member asks it for both steps and issues its own session. `SIGN_IN_WAYS`
says which ways the register offers, the instance's basics and the ways
in carry `simpleLogin`, GitHub links nobody more where SimpleLogin is
offered, and Learn's and Todo's pruning forgets the unfinished sign-ins
hourly. No migration: the tables are halkyon_oidc's, already in place.

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

packages/halkyon_base_server/test/integration/test_tools/serverpod_test_tools.dart

@@ -46,6 +46,11 @@ import 'package:halkyon_base_server/src/generated/profile/profile.dart'
     as _it4tom37;
 import 'package:halkyon_base_server/src/generated/profile/profile_refusal.dart'
     as _idszjcpz;
+import 'package:halkyon_base_server/src/generated/simplelogin/simplelogin_completed.dart'
+    as _i8g1l2iv;
+import 'package:halkyon_base_server/src/generated/simplelogin/simplelogin_platform.dart'
+    as _ixrtiuh0;
+import 'package:halkyon_oidc_server/halkyon_oidc_server.dart' as _ipoqfiqr;
 import 'package:serverpod/serverpod.dart' as _is;
 import 'package:serverpod_auth_core_server/serverpod_auth_core_server.dart'
     as _iacs;
@@ -206,6 +211,8 @@ class TestEndpoints {
   late final _ProfileEndpoint profile;
 
   late final _ProfilesEndpoint profiles;
+
+  late final _SimpleLoginEndpoint simpleLogin;
 }
 
 class _InternalTestEndpoints extends TestEndpoints
@@ -263,6 +270,10 @@ class _InternalTestEndpoints extends TestEndpoints
       endpoints,
       serializationManager,
     );
+    simpleLogin = _SimpleLoginEndpoint(
+      endpoints,
+      serializationManager,
+    );
   }
 }
 
@@ -1574,3 +1585,80 @@ class _ProfilesEndpoint {
     });
   }
 }
+
+class _SimpleLoginEndpoint {
+  _SimpleLoginEndpoint(
+    this._endpointDispatch,
+    this._serializationManager,
+  );
+
+  final _is.EndpointDispatch _endpointDispatch;
+
+  final _is.SerializationManager _serializationManager;
+
+  _ida.Future<_ipoqfiqr.OidcStart> begin(
+    _ist.TestSessionBuilder sessionBuilder, {
+    required _ixrtiuh0.SimpleLoginPlatform platform,
+  }) async {
+    return _ist.callAwaitableFunctionAndHandleExceptions(() async {
+      var _localUniqueSession =
+          (sessionBuilder as _ist.InternalTestSessionBuilder).internalBuild(
+            endpoint: 'simpleLogin',
+            method: 'begin',
+          );
+      try {
+        var _localCallContext = await _endpointDispatch.getMethodCallContext(
+          createSessionCallback: (_) => _localUniqueSession,
+          endpointPath: 'simpleLogin',
+          methodName: 'begin',
+          parameters: _ist.testObjectToJson({'platform': platform}),
+          serializationManager: _serializationManager,
+        );
+        var _localReturnValue =
+            await (_localCallContext.method.call(
+                  _localUniqueSession,
+                  _localCallContext.arguments,
+                )
+                as _ida.Future<_ipoqfiqr.OidcStart>);
+        return _localReturnValue;
+      } finally {
+        await _localUniqueSession.close();
+      }
+    });
+  }
+
+  _ida.Future<_i8g1l2iv.SimpleLoginCompleted> complete(
+    _ist.TestSessionBuilder sessionBuilder, {
+    required _is.UuidValue attempt,
+    required String code,
+  }) async {
+    return _ist.callAwaitableFunctionAndHandleExceptions(() async {
+      var _localUniqueSession =
+          (sessionBuilder as _ist.InternalTestSessionBuilder).internalBuild(
+            endpoint: 'simpleLogin',
+            method: 'complete',
+          );
+      try {
+        var _localCallContext = await _endpointDispatch.getMethodCallContext(
+          createSessionCallback: (_) => _localUniqueSession,
+          endpointPath: 'simpleLogin',
+          methodName: 'complete',
+          parameters: _ist.testObjectToJson({
+            'attempt': attempt,
+            'code': code,
+          }),
+          serializationManager: _serializationManager,
+        );
+        var _localReturnValue =
+            await (_localCallContext.method.call(
+                  _localUniqueSession,
+                  _localCallContext.arguments,
+                )
+                as _ida.Future<_i8g1l2iv.SimpleLoginCompleted>);
+        return _localReturnValue;
+      } finally {
+        await _localUniqueSession.close();
+      }
+    });
+  }
+}