feat(privacy): the instance's side of private studysets (ADR 0019)

- `content_key`, a synced table in the person's space, keeps their data keys
  sealed to their account (a private studyset's, their personal one);
  `learning_path_answer` gains `keyId` and `nonce` for answers in private
  studysets. Additive only, on the server and the device.
- Publishing refuses a private studyset, and a tree holding a private row
  (`PublishRefusal.private`); a private studyset elsewhere no longer breaks
  publishing a readable one. Encrypted tags are named as the device names
  them (`tagNames`): a name for a tag that isn't the person's, or an
  encrypted tag of the release without one, refuses it
  (`tagNamesMismatch`); a readable tag keeps its own name.
- The connector leaves private studysets out and says how many there are.
- The learner count reads no payload any more: Count me is kept by the
  instance (`counted_learner`) and the device reports which publications
  its copies come from (`learning_copy`, accepted only while counted, each
  report replacing the last); only the reporter's own studysets count.
  Deleting a person deletes both.
- An upload says whether its file is encrypted: only a readable one over
  20 MB is checked to be a PDF, and an encrypted one may be 4 KiB larger.

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/learn/halkyon_learn_server/test/integration/test_tools/serverpod_test_tools.dart

@@ -38,6 +38,8 @@ import 'package:halkyon_learn_server/src/generated/discussion/discussion_target.
     as _ike2gc23;
 import 'package:halkyon_learn_server/src/generated/discussion/discussion_view.dart'
     as _ikk5e562;
+import 'package:halkyon_learn_server/src/generated/explore/copy_report.dart'
+    as _ipludy4j;
 import 'package:halkyon_learn_server/src/generated/explore/explore_entry.dart'
     as _iscq690j;
 import 'package:halkyon_learn_server/src/generated/explore/explore_query.dart'
@@ -205,6 +207,8 @@ class TestEndpoints {
 
   late final _ExploreEndpoint explore;
 
+  late final _LearningCountEndpoint learningCount;
+
   late final _FeedbackEndpoint feedback;
 
   late final _InboxEndpoint inbox;
@@ -249,6 +253,10 @@ class _InternalTestEndpoints extends TestEndpoints
       endpoints,
       serializationManager,
     );
+    learningCount = _LearningCountEndpoint(
+      endpoints,
+      serializationManager,
+    );
     feedback = _FeedbackEndpoint(
       endpoints,
       serializationManager,
@@ -291,8 +299,9 @@ class _AssetEndpoint {
   _ida.Future<String?> startUpload(
     _ist.TestSessionBuilder sessionBuilder,
     String sha256,
-    int byteSize,
-  ) async {
+    int byteSize, {
+    bool? encrypted,
+  }) async {
     return _ist.callAwaitableFunctionAndHandleExceptions(() async {
       var _localUniqueSession =
           (sessionBuilder as _ist.InternalTestSessionBuilder).internalBuild(
@@ -307,6 +316,7 @@ class _AssetEndpoint {
           parameters: _ist.testObjectToJson({
             'sha256': sha256,
             'byteSize': byteSize,
+            'encrypted': encrypted,
           }),
           serializationManager: _serializationManager,
         );
@@ -325,8 +335,9 @@ class _AssetEndpoint {
 
   _ida.Future<bool> finishUpload(
     _ist.TestSessionBuilder sessionBuilder,
-    String sha256,
-  ) async {
+    String sha256, {
+    bool? encrypted,
+  }) async {
     return _ist.callAwaitableFunctionAndHandleExceptions(() async {
       var _localUniqueSession =
           (sessionBuilder as _ist.InternalTestSessionBuilder).internalBuild(
@@ -338,7 +349,10 @@ class _AssetEndpoint {
           createSessionCallback: (_) => _localUniqueSession,
           endpointPath: 'asset',
           methodName: 'finishUpload',
-          parameters: _ist.testObjectToJson({'sha256': sha256}),
+          parameters: _ist.testObjectToJson({
+            'sha256': sha256,
+            'encrypted': encrypted,
+          }),
           serializationManager: _serializationManager,
         );
         var _localReturnValue =
@@ -1535,6 +1549,107 @@ class _ExploreEndpoint {
   }
 }
 
+class _LearningCountEndpoint {
+  _LearningCountEndpoint(
+    this._endpointDispatch,
+    this._serializationManager,
+  );
+
+  final _is.EndpointDispatch _endpointDispatch;
+
+  final _is.SerializationManager _serializationManager;
+
+  _ida.Future<bool> counted(_ist.TestSessionBuilder sessionBuilder) async {
+    return _ist.callAwaitableFunctionAndHandleExceptions(() async {
+      var _localUniqueSession =
+          (sessionBuilder as _ist.InternalTestSessionBuilder).internalBuild(
+            endpoint: 'learningCount',
+            method: 'counted',
+          );
+      try {
+        var _localCallContext = await _endpointDispatch.getMethodCallContext(
+          createSessionCallback: (_) => _localUniqueSession,
+          endpointPath: 'learningCount',
+          methodName: 'counted',
+          parameters: _ist.testObjectToJson({}),
+          serializationManager: _serializationManager,
+        );
+        var _localReturnValue =
+            await (_localCallContext.method.call(
+                  _localUniqueSession,
+                  _localCallContext.arguments,
+                )
+                as _ida.Future<bool>);
+        return _localReturnValue;
+      } finally {
+        await _localUniqueSession.close();
+      }
+    });
+  }
+
+  _ida.Future<void> setCounted(
+    _ist.TestSessionBuilder sessionBuilder,
+    bool counted,
+  ) async {
+    return _ist.callAwaitableFunctionAndHandleExceptions(() async {
+      var _localUniqueSession =
+          (sessionBuilder as _ist.InternalTestSessionBuilder).internalBuild(
+            endpoint: 'learningCount',
+            method: 'setCounted',
+          );
+      try {
+        var _localCallContext = await _endpointDispatch.getMethodCallContext(
+          createSessionCallback: (_) => _localUniqueSession,
+          endpointPath: 'learningCount',
+          methodName: 'setCounted',
+          parameters: _ist.testObjectToJson({'counted': counted}),
+          serializationManager: _serializationManager,
+        );
+        var _localReturnValue =
+            await (_localCallContext.method.call(
+                  _localUniqueSession,
+                  _localCallContext.arguments,
+                )
+                as _ida.Future<void>);
+        return _localReturnValue;
+      } finally {
+        await _localUniqueSession.close();
+      }
+    });
+  }
+
+  _ida.Future<bool> reportCopies(
+    _ist.TestSessionBuilder sessionBuilder,
+    List<_ipludy4j.CopyReport> copies,
+  ) async {
+    return _ist.callAwaitableFunctionAndHandleExceptions(() async {
+      var _localUniqueSession =
+          (sessionBuilder as _ist.InternalTestSessionBuilder).internalBuild(
+            endpoint: 'learningCount',
+            method: 'reportCopies',
+          );
+      try {
+        var _localCallContext = await _endpointDispatch.getMethodCallContext(
+          createSessionCallback: (_) => _localUniqueSession,
+          endpointPath: 'learningCount',
+          methodName: 'reportCopies',
+          parameters: _ist.testObjectToJson({'copies': copies}),
+          serializationManager: _serializationManager,
+        );
+        var _localReturnValue =
+            await (_localCallContext.method.call(
+                  _localUniqueSession,
+                  _localCallContext.arguments,
+                )
+                as _ida.Future<bool>);
+        return _localReturnValue;
+      } finally {
+        await _localUniqueSession.close();
+      }
+    });
+  }
+}
+
 class _FeedbackEndpoint {
   _FeedbackEndpoint(
     this._endpointDispatch,
@@ -1922,6 +2037,7 @@ class _PublishEndpoint {
     String slug,
     String notes, {
     String? description,
+    Map<String, String>? tagNames,
   }) async {
     return _ist.callAwaitableFunctionAndHandleExceptions(() async {
       var _localUniqueSession =
@@ -1939,6 +2055,7 @@ class _PublishEndpoint {
             'slug': slug,
             'notes': notes,
             'description': description,
+            'tagNames': tagNames,
           }),
           serializationManager: _serializationManager,
         );