feat(flutter): isar integration (#9181)

* Add isar page

* Update docs/platforms/flutter/integrations/isar-instrumentation.mdx

Co-authored-by: vivianyentran <20403606+vivianyentran@users.noreply.github.com>

* Update isar-instrumentation.mdx

* update text

---------

Co-authored-by: Giancarlo Buenaflor <giancarlo_buenaflor@yahoo.com>
Co-authored-by: vivianyentran <20403606+vivianyentran@users.noreply.github.com>

Author: 3 people

docs/platforms/flutter/integrations/isar-instrumentation.mdx

@@ -0,0 +1,99 @@
+---
+title: Isar Database Instrumentation
+description: "Learn more about the Sentry Isar Database Instrumentation for the Flutter SDK."
+caseStyle: camelCase
+supportLevel: production
+sdk: sentry.dart.flutter
+categories:
+  - mobile
+---
+
+<Include name="feature-stage-beta.mdx" />
+
+_(New in version 7.16.0)_
+
+Isar is a fast cross-platform database for Flutter.
+The [sentry_isar](https://pub.dev/packages/sentry_isar) package provides `Isar` support for database instrumentation and allows you to track the performance of your queries.
+
+## Instrumentation Behaviour
+
+The created spans will be attached to the transaction on the scope. If no transaction is on the scope the Isar span will not be sent to Sentry.
+
+## Prerequisites
+
+Before starting, ensure:
+
+1. The Sentry Flutter SDK is initialized. Learn more [here](/platforms/flutter/#configure).
+2. Performance Monitoring is set up. Learn more [here](/platforms/flutter/performance/).
+
+## Install
+
+Add the `sentry_isar` dependency to install the Isar database instrumentation.
+
+```yml {filename:pubspec.yaml}
+dependencies:
+sentry_flutter: ^{{@inject packages.version('sentry.dart.flutter', '7.16.0') }}
+sentry_isar: ^{{@inject packages.version('sentry.dart.isar', '7.16.0') }}
+path_provider: ^2.0.0
+```
+
+## Configure
+
+Use `SentryIsar` to initialize the instance:
+
+```dart
+import 'package:path_provider/path_provider.dart';
+import 'package:sentry_flutter/sentry_flutter.dart';
+import 'package:sentry_isar/sentry_isar.dart';
+
+import 'user.dart'; // Import your Isar model instead
+
+final dir = await getApplicationDocumentsDirectory();
+final isar = await SentryIsar.open(
+  [UserSchema],
+  directory: dir.path,
+);
+```
+
+## Verify
+
+### 1. Execute the Code
+
+```dart
+import 'package:path_provider/path_provider.dart';
+import 'package:sentry_flutter/sentry_flutter.dart';
+import 'package:sentry_isar/sentry_isar.dart';
+
+import 'user.dart'; // Import your Isar model instead
+
+Future<void> runApp() async {
+  final tr = Sentry.startTransaction('isarTest', 'db', bindToScope: true);
+
+  final dir = await getApplicationDocumentsDirectory();
+
+  final isar = await SentryIsar.open(
+    [UserSchema],
+    directory: dir.path,
+  );
+
+  final newUser = User()
+    ..name = 'Joe Dirt'
+    ..age = 36;
+
+  await isar.writeTxn(() async {
+    await isar.users.put(newUser); // insert & update
+  });
+
+  final existingUser = await isar.users.get(newUser.id); // get
+
+  await isar.writeTxn(() async {
+    await isar.users.delete(existingUser!.id); // delete
+  });
+
+  await tr.finish(status: const SpanStatus.ok());
+}
+```
+
+### 2. View the Transaction on Sentry.io
+
+To view the recorded transaction, log into [sentry.io](https://sentry.io). Use the left sidebar to navigate to the **Performance** page. Select your project and scroll down to the transactions table to see the just recorded transaction with the name `isarTest`. You can also use the search bar to find the transaction. Click on the transaction to open its **Transaction Summary** page for more performance details.