feat(meditate): dreams on the server, sealed and synced like the sittings

The dream journal's table (ADR 0038, D14): `dream`, in the sync engine's
database, a row a dream, its content sealed on the device (key ID,
payload, nonce), so the instance sees only that a dream exists, its size
and when it changed. The same rules as the sittings: the sync engine's
connector refuses a call without a session, each row lives in its
person's space, and deleting the person deletes their dreams with it
(the deletion test now writes and counts a dream too, and leaves
another person's).

The migration `20261103130213716-dreams`:
- `CREATE OR REPLACE FUNCTION gen_random_uuid_v7()`: the generator
  repeats the UUID v7 function every migration; replacing it with the
  same body changes nothing.
- `CREATE TABLE "dream"`: `id` a UUID v7 by default, `spaceId` the
  person's sync space, `keyId` the key it is sealed with, `payload` the
  sealed bytes (not null), `nonce` the sealing's nonce.
- `CREATE INDEX "dream_space_idx"` on `spaceId`, so deleting a space
  finds its dreams without scanning the table.
- The foreign key from `spaceId` to `offline_sync_spaces("id")` with
  `ON DELETE CASCADE`: deleting the space deletes its dreams.
- The version rows of every module in `serverpod_migrations`.
A new, empty table: nothing existing changes and no data moves.

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/meditate/halkyon_meditate_client/lib/src/protocol/protocol.dart

@@ -21,9 +21,11 @@ import 'package:serverpod_client/serverpod_client.dart' as _isc;
 import 'package:serverpod_database/serverpod_database.dart' as _isd;
 import 'package:serverpod_offline_sync_client/serverpod_offline_sync_client.dart'
     as _ipulbpi2;
+import 'journal/dream.dart' as _is2va3v7;
 import 'privacy/content_key.dart' as _imed3x5d;
 import 'settings/meditate_settings.dart' as _iutacwgf;
 import 'sitting/sitting.dart' as _ic8w2fbu;
+export 'journal/dream.dart';
 export 'privacy/content_key.dart';
 export 'settings/meditate_settings.dart';
 export 'sitting/sitting.dart';
@@ -99,6 +101,73 @@ class Protocol extends _isd.DatabaseSerializationManager {
       ],
       managed: true,
     ),
+    _isd.TableDefinition(
+      name: 'dream',
+      dartName: 'Dream',
+      schema: 'public',
+      module: 'halkyon_meditate',
+      columns: [
+        _isd.ColumnDefinition(
+          name: 'id',
+          columnType: _isd.ColumnType.uuid,
+          isNullable: false,
+          dartType: 'UuidValue?',
+          columnDefault: 'random_v7',
+        ),
+        _isd.ColumnDefinition(
+          name: 'spaceId',
+          columnType: _isd.ColumnType.bigint,
+          isNullable: true,
+          dartType: 'int?',
+        ),
+        _isd.ColumnDefinition(
+          name: 'keyId',
+          columnType: _isd.ColumnType.text,
+          isNullable: true,
+          dartType: 'String?',
+        ),
+        _isd.ColumnDefinition(
+          name: 'payload',
+          columnType: _isd.ColumnType.bytea,
+          isNullable: false,
+          dartType: 'dart:typed_data:ByteData',
+        ),
+        _isd.ColumnDefinition(
+          name: 'nonce',
+          columnType: _isd.ColumnType.bytea,
+          isNullable: true,
+          dartType: 'dart:typed_data:ByteData?',
+        ),
+      ],
+      foreignKeys: [
+        _isd.ForeignKeyDefinition(
+          constraintName: 'dream_fk_0',
+          columns: ['spaceId'],
+          referenceTable: 'offline_sync_spaces',
+          referenceTableSchema: 'public',
+          referenceColumns: ['id'],
+          onUpdate: _isd.ForeignKeyAction.noAction,
+          onDelete: _isd.ForeignKeyAction.cascade,
+          matchType: null,
+        ),
+      ],
+      indexes: [
+        _isd.IndexDefinition(
+          indexName: 'dream_space_idx',
+          tableSpace: null,
+          elements: [
+            _isd.IndexElementDefinition(
+              type: _isd.IndexElementDefinitionType.column,
+              definition: 'spaceId',
+            ),
+          ],
+          type: 'btree',
+          isUnique: false,
+          isPrimary: false,
+        ),
+      ],
+      managed: true,
+    ),
     _isd.TableDefinition(
       name: 'meditate_settings',
       dartName: 'MeditateSettings',
@@ -282,6 +351,9 @@ class Protocol extends _isd.DatabaseSerializationManager {
       }
     }
 
+    if (t == _is2va3v7.Dream) {
+      return _is2va3v7.Dream.fromJson(data) as T;
+    }
     if (t == _imed3x5d.ContentKey) {
       return _imed3x5d.ContentKey.fromJson(data) as T;
     }
@@ -291,6 +363,9 @@ class Protocol extends _isd.DatabaseSerializationManager {
     if (t == _ic8w2fbu.Sitting) {
       return _ic8w2fbu.Sitting.fromJson(data) as T;
     }
+    if (t == _isc.getType<_is2va3v7.Dream?>()) {
+      return (data != null ? _is2va3v7.Dream.fromJson(data) : null) as T;
+    }
     if (t == _isc.getType<_imed3x5d.ContentKey?>()) {
       return (data != null ? _imed3x5d.ContentKey.fromJson(data) : null) as T;
     }
@@ -321,6 +396,7 @@ class Protocol extends _isd.DatabaseSerializationManager {
 
   static String? getClassNameForType(Type type) {
     return switch (type) {
+      _is2va3v7.Dream => 'Dream',
       _imed3x5d.ContentKey => 'ContentKey',
       _iutacwgf.MeditateSettings => 'MeditateSettings',
       _ic8w2fbu.Sitting => 'Sitting',
@@ -341,6 +417,8 @@ class Protocol extends _isd.DatabaseSerializationManager {
     }
 
     switch (data) {
+      case _is2va3v7.Dream():
+        return 'Dream';
       case _imed3x5d.ContentKey():
         return 'ContentKey';
       case _iutacwgf.MeditateSettings():
@@ -383,6 +461,9 @@ class Protocol extends _isd.DatabaseSerializationManager {
     if (dataClassName is! String) {
       return super.deserializeByClassName(data);
     }
+    if (dataClassName == 'Dream') {
+      return deserialize<_is2va3v7.Dream>(data['data']);
+    }
     if (dataClassName == 'ContentKey') {
       return deserialize<_imed3x5d.ContentKey>(data['data']);
     }
@@ -471,6 +552,8 @@ class Protocol extends _isd.DatabaseSerializationManager {
       }
     }
     switch (t) {
+      case _is2va3v7.Dream:
+        return _is2va3v7.Dream.t;
       case _imed3x5d.ContentKey:
         return _imed3x5d.ContentKey.t;
       case _iutacwgf.MeditateSettings: