Add doc about the cache viewer

docs/source/testing/android-studio-plugin.mdx

@@ -85,6 +85,20 @@ For the plugin to be able to fetch the metrics, you need to configure your proje
 - API key: should start with `service:` or `user:`
 - Graph ID: can be found on your graph page in Apollo Studio or is filled automatically if you provide a `service:` API key
 
+### Normalized cache viewer
+
+The plugin provides a graphical tool to inspect a normalized cache database. To open it, go to <kbd>View</kbd> | <kbd>
+Tool Windows</kbd> | <kbd>Apollo Normalized Cache</kbd>.
+From there you can either drag and drop a `.db` file to the tool window to open it, or click on "Open file..." to pick
+the file to open.
+
+There is also a "Pull from device" option to pull the cache database from a connected device or emulator.
+
+Once the cache is open, you can search for a record by ID, or browse them from the left side. Clicking on a record will
+show its fields and their values on the right side.
+
+<img src="images/cache-viewer.png" width="640" alt="Normalized cache viewer"/>
+
 ## Weekly snapshots
 
 If you wish to try the latest features, you can install the weekly snapshots. To do so, add the following repository in <kbd>Settings</kbd> | <kbd>Plugins</kbd> | <kbd>⚙</kbd>️ | <kbd>Manage Plugin Repositories</kbd> | <kbd>+</kbd>: `https://raw.githubusercontent.com/apollographql/apollo-kotlin/main/intellij-plugin/snapshots/plugins.xml`.

intellij-plugin/README.md

@@ -13,6 +13,7 @@ This plugin for Android Studio and IntelliJ helps you work with the
 - Integration with the [GraphQL IntelliJ Plugin](https://plugins.jetbrains.com/plugin/8097-js-graphql): the structure of the Apollo project is automatically contributed, so there is no need to create a `graphql.config.yml` / `.graphqlconfig` file
 - Navigation Kotlin code ⇄ GraphQL definitions
 - Unused operations and fields highlighting
+- Normalized cache viewer
 - Migration helpers:
   - Apollo Android 2.x → Apollo Kotlin 3.x
   - Apollo Kotlin 3.x → Apollo Kotlin 4.x