feat(server): runtime setting support (#5602)

---

<details open="true"><summary>Generated summary (powered by <a href="https://app.graphite.dev">Graphite</a>)</summary>

> ## TL;DR
> This pull request adds a new migration file, a new model, and new modules related to runtime settings. It also introduces a new `Runtime` service that allows getting, setting, and updating runtime configurations.
>
> ## What changed
> - Added a new migration file `migration.sql` that creates a table called `application_settings` with columns `key` and `value`.
> - Added a new model `ApplicationSetting` with properties `key` and `value`.
> - Added a new module `RuntimeSettingModule` that exports the `Runtime` service.
> - Added a new service `Runtime` that provides methods for getting, setting, and updating runtime configurations.
> - Modified the `app.module.ts` file to import the `RuntimeSettingModule`.
> - Modified the `index.ts` file in the `fundamentals` directory to export the `Runtime` service.
> - Added a new file `def.ts` in the `runtime` directory that defines the runtime configurations and provides a default implementation.
> - Added a new file `service.ts` in the `runtime` directory that implements the `Runtime` service.
>
> ## How to test
> 1. Run the migration script to create the `application_settings` table.
> 2. Use the `Runtime` service to get, set, and update runtime configurations.
> 3. Verify that the runtime configurations are stored correctly in the database and can be retrieved and modified using the `Runtime` service.
>
> ## Why make this change
> This change introduces a new feature related to runtime settings. The `Runtime` service allows the application to dynamically manage and modify runtime configurations without requiring a restart. This provides flexibility and allows for easier customization and configuration of the application.
</details>

packages/backend/server/src/core/doc/config.ts

@@ -0,0 +1,71 @@
+import {
+  defineRuntimeConfig,
+  defineStartupConfig,
+  ModuleConfig,
+} from '../../fundamentals/config';
+
+interface DocStartupConfigurations {
+  manager: {
+    /**
+     * Whether auto merge updates into doc snapshot.
+     */
+    enableUpdateAutoMerging: boolean;
+
+    /**
+     * How often the [DocManager] will start a new turn of merging pending updates into doc snapshot.
+     *
+     * This is not the latency a new joint client will take to see the latest doc,
+     * but the buffer time we introduced to reduce the load of our service.
+     *
+     * in {ms}
+     */
+    updatePollInterval: number;
+
+    /**
+     * The maximum number of updates that will be pulled from the server at once.
+     * Existing for avoiding the server to be overloaded when there are too many updates for one doc.
+     */
+    maxUpdatesPullCount: number;
+  };
+  history: {
+    /**
+     * How long the buffer time of creating a new history snapshot when doc get updated.
+     *
+     * in {ms}
+     */
+    interval: number;
+  };
+}
+
+interface DocRuntimeConfigurations {
+  /**
+   * Use `y-octo` to merge updates at the same time when merging using Yjs.
+   *
+   * This is an experimental feature, and aimed to check the correctness of JwstCodec.
+   */
+  experimentalMergeWithYOcto: boolean;
+}
+
+declare module '../../fundamentals/config' {
+  interface AppConfig {
+    doc: ModuleConfig<DocStartupConfigurations, DocRuntimeConfigurations>;
+  }
+}
+
+defineStartupConfig('doc', {
+  manager: {
+    enableUpdateAutoMerging: true,
+    updatePollInterval: 1000,
+    maxUpdatesPullCount: 100,
+  },
+  history: {
+    interval: 1000,
+  },
+});
+
+defineRuntimeConfig('doc', {
+  experimentalMergeWithYOcto: {
+    desc: 'Use `y-octo` to merge updates at the same time when merging using Yjs.',
+    default: false,
+  },
+});

packages/backend/server/src/core/doc/index.ts

@@ -1,3 +1,5 @@
+import './config';
+
 import { Module } from '@nestjs/common';
 
 import { QuotaModule } from '../quota';

packages/backend/server/src/core/doc/manager.ts

@@ -133,8 +133,11 @@ export class DocManager implements OnModuleInit, OnModuleDestroy {
   private async applyUpdates(guid: string, ...updates: Buffer[]): Promise<Doc> {
     const doc = await this.recoverDoc(...updates);
 
+    const useYocto = await this.config.runtime.fetch(
+      'doc/experimentalMergeWithYOcto'
+    );
     // test jwst codec
-    if (this.config.doc.manager.experimentalMergeWithYOcto) {
+    if (useYocto) {
       metrics.jwst.counter('codec_merge_counter').add(1);
       const yjsResult = Buffer.from(encodeStateAsUpdate(doc));
       let log = false;
@@ -185,11 +188,6 @@ export class DocManager implements OnModuleInit, OnModuleDestroy {
     }, this.config.doc.manager.updatePollInterval);
 
     this.logger.log('Automation started');
-    if (this.config.doc.manager.experimentalMergeWithYOcto) {
-      this.logger.warn(
-        'Experimental feature enabled: merge updates with jwst codec is enabled'
-      );
-    }
   }
 
   /**