20215 convert application variable to a syncable entity (#20269)

##  Summary

- Converts applicationVariable from a bespoke sync path to a proper
SyncableEntity,
unifying it with the workspace migration pipeline used by all other
manifest-managed
  entities (agent, skill, frontComponent, webhook, etc.)
- Removes the upsertManyApplicationVariableEntities method and its
direct-DB-mutation
approach in favor of the standard validate → build → run action handler
pipeline
- Adds universalIdentifier, deletedAt columns and makes applicationId
NOT NULL via an
  instance command migration

##  Motivation

Before this change, applicationVariable was the only manifest-managed
entity that bypassed
ApplicationManifestMigrationService.syncMetadataFromManifest(). It used
a bespoke service
method called directly from syncApplication(), creating two mental
models, two validation
styles, and two cache invalidation patterns. Now there's one unified
pipeline for all
  manifest entities.

##  What changed

###  Entity refactor:
- ApplicationVariableEntity now extends SyncableEntity (gains
universalIdentifier,
  non-nullable applicationId with CASCADE, soft-delete via deletedAt)

###  New flat entity layer (flat-application-variable/):
- Type, maps type, editable properties constant, entity-to-flat
converter, cache service,
  module

###  New migration pipeline wiring:
- Manifest converter
(fromApplicationVariableManifestToUniversalFlatApplicationVariable)
  - Validator service (FlatApplicationVariableValidatorService)
- Builder service
(WorkspaceMigrationApplicationVariableActionsBuilderService)
  - Create/Update/Delete action handlers with secret encryption hooks
- Registered in orchestrator, builder module, runner module, and all
type registries

###  Removed bespoke path:
- Deleted upsertManyApplicationVariableEntities from
ApplicationVariableEntityService
  - Removed its call from ApplicationSyncService.syncApplication()
- Kept update() (operator-set value at runtime) and getDisplayValue()
(runtime display)

###  Database migration:
- Instance command to add columns, backfill universalIdentifier, enforce
NOT NULL
  constraints, and update indexes

##  Test plan

  - npx nx typecheck twenty-server passes (0 errors)
- Unit tests pass (application-variable.service.spec.ts,
build-env-var.spec.ts)
- Install an app with applicationVariables in its manifest → variables
appear with correct
  universalIdentifier
- Update app manifest (add/remove/modify a variable) → migration
pipeline handles diff
  correctly
- Operator-set value via update endpoint persists correctly with
encryption
  - Uninstall app → variables cascade-deleted
  - app dev --once on example app syncs without errors

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/__tests__/__snapshots__/all-universal-flat-entity-properties-to-compare-and-stringify.constant.spec.ts.snap

@@ -20,6 +20,14 @@ exports[`ALL_UNIVERSAL_FLAT_ENTITY_PROPERTIES_TO_COMPARE_AND_STRINGIFY should ma
       "evaluationInputs",
     ],
   },
+  "applicationVariable": {
+    "propertiesToCompare": [
+      "key",
+      "description",
+      "isSecret",
+    ],
+    "propertiesToStringify": [],
+  },
   "commandMenuItem": {
     "propertiesToCompare": [
       "label",

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-entity-properties-configuration-by-metadata-name.constant.ts

@@ -1542,6 +1542,38 @@ export const ALL_ENTITY_PROPERTIES_CONFIGURATION_BY_METADATA_NAME = {
       universalProperty: undefined,
     },
   },
+  applicationVariable: {
+    key: {
+      toCompare: true,
+      toStringify: false,
+      universalProperty: undefined,
+    },
+    value: {
+      toCompare: false,
+      toStringify: false,
+      universalProperty: undefined,
+    },
+    description: {
+      toCompare: true,
+      toStringify: false,
+      universalProperty: undefined,
+    },
+    isSecret: {
+      toCompare: true,
+      toStringify: false,
+      universalProperty: undefined,
+    },
+    createdAt: {
+      toCompare: false,
+      toStringify: false,
+      universalProperty: undefined,
+    },
+    updatedAt: {
+      toCompare: false,
+      toStringify: false,
+      universalProperty: undefined,
+    },
+  },
   connectionProvider: {
     name: { toCompare: true, toStringify: false, universalProperty: undefined },
     displayName: {

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-many-to-one-metadata-foreign-key.constant.ts

@@ -275,6 +275,10 @@ export const ALL_MANY_TO_ONE_METADATA_FOREIGN_KEY = {
     workspace: null,
     application: null,
   },
+  applicationVariable: {
+    workspace: null,
+    application: null,
+  },
   viewSort: {
     application: null,
     workspace: null,

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-many-to-one-metadata-relations.constant.ts

@@ -487,6 +487,10 @@ export const ALL_MANY_TO_ONE_METADATA_RELATIONS = {
     workspace: null,
     application: null,
   },
+  applicationVariable: {
+    workspace: null,
+    application: null,
+  },
   viewSort: {
     application: null,
     workspace: null,

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-metadata-entity-by-metadata-name.constant.ts

@@ -3,6 +3,7 @@ import { type EntityTarget, type ObjectLiteral } from 'typeorm';
 
 import { ConnectionProviderEntity } from 'src/engine/core-modules/application/connection-provider/connection-provider.entity';
 import { AgentEntity } from 'src/engine/metadata-modules/ai/ai-agent/entities/agent.entity';
+import { ApplicationVariableEntity } from 'src/engine/core-modules/application/application-variable/application-variable.entity';
 import { CommandMenuItemEntity } from 'src/engine/metadata-modules/command-menu-item/entities/command-menu-item.entity';
 import { FieldMetadataEntity } from 'src/engine/metadata-modules/field-metadata/field-metadata.entity';
 import { FrontComponentEntity } from 'src/engine/metadata-modules/front-component/entities/front-component.entity';
@@ -57,6 +58,7 @@ export const ALL_METADATA_ENTITY_BY_METADATA_NAME = {
   navigationMenuItem: NavigationMenuItemEntity,
   permissionFlag: PermissionFlagEntity,
   webhook: WebhookEntity,
+  applicationVariable: ApplicationVariableEntity,
   viewSort: ViewSortEntity,
   connectionProvider: ConnectionProviderEntity,
 } as const satisfies Record<AllMetadataName, EntityTarget<ObjectLiteral>>;

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-metadata-required-metadata-for-validation.constant.ts

@@ -112,5 +112,6 @@ export const ALL_METADATA_REQUIRED_METADATA_FOR_VALIDATION = {
   },
   frontComponent: {},
   webhook: {},
+  applicationVariable: {},
   connectionProvider: {},
 } as const satisfies MetadataRequiredForValidation;

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-metadata-serialized-relation.constant.ts

@@ -50,6 +50,7 @@ export const ALL_METADATA_SERIALIZED_RELATION = {
   viewSort: {},
   frontComponent: {},
   webhook: {},
+  applicationVariable: {},
   connectionProvider: {},
 } as const satisfies MetadataSerializedRelationProperties;
 

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-one-to-many-metadata-relations.constant.ts

@@ -243,6 +243,7 @@ export const ALL_ONE_TO_MANY_METADATA_RELATIONS = {
   },
   frontComponent: {},
   webhook: {},
+  applicationVariable: {},
   viewSort: {},
   connectionProvider: {},
 } as const satisfies OneToManyMetadataRelationsProperties;