Feat(modules-sdk): Run hooks on application start (#6111)

**What**
- run `onApplicationStart` hook when starting modules

.changeset/neat-seals-help.md

@@ -0,0 +1,5 @@
+---
+"@medusajs/modules-sdk": patch
+---
+
+feat(modules-sdk): run hooks on application start

packages/modules-sdk/src/medusa-app.ts

@@ -308,6 +308,7 @@ export async function MedusaApp(
       }))
   }
 
+  try {
     return {
       modules: allModules,
       link: remoteLink,
@@ -316,4 +317,7 @@ export async function MedusaApp(
       notFound,
       runMigrations,
     }
+  } finally {
+    await MedusaModule.onApplicationStart()
+  }
 }

packages/modules-sdk/src/medusa-module.ts

@@ -1,5 +1,6 @@
 import {
   ExternalModuleDeclaration,
+  IModuleService,
   InternalModuleDeclaration,
   LinkModuleDefinition,
   LoadedModule,
@@ -86,6 +87,21 @@ export class MedusaModule {
     })
   }
   
+  public static onApplicationStart(): void {
+    for (const instances of MedusaModule.instances_.values()) {
+      for (const instance of Object.values(instances) as IModuleService[]) {
+        if (instance?.__hooks) {
+          instance.__hooks?.onApplicationStart
+            ?.bind(instance)()
+            .catch(() => {
+              // The module should handle this and log it
+              return void 0
+            })
+        }
+      }
+    }
+  }
+
   public static clearInstances(): void {
     MedusaModule.instances_.clear()
     MedusaModule.modules_.clear()