Add checksum to manifest (#17368)

## Refactor app-dev state management and build utilities

- Store only `manifest` in `AppDevState` instead of full
`ManifestBuildResult`; add `sourcePath` to `FileStatus`
- Pass `sourcePaths` directly to watchers instead of
`ManifestBuildResult`
- Only reset `fileUploadStatus` for functions/components when their
source paths change
- Add pure `updateManifestChecksum` utility that returns a new manifest
without side effects
- Extract `processEsbuildResult` to deduplicate build result processing
between watchers
- Rename `serverlessFunctions` → `functions` in SDK code (API unchanged)
- Extract `writeManifestToOutput` to shared `manifest-writer.ts`

packages/twenty-server/src/engine/core-modules/application/application-sync.service.ts

@@ -105,7 +105,7 @@ export class ApplicationSyncService {
       });
     }
 
-    if (manifest.serverlessFunctions.length > 0) {
+    if (manifest.functions.length > 0) {
       if (!isDefined(application.serverlessFunctionLayerId)) {
         throw new ApplicationException(
           `Failed to sync serverless function, could not find a serverless function layer.`,
@@ -114,7 +114,7 @@ export class ApplicationSyncService {
       }
 
       await this.syncServerlessFunctions({
-        serverlessFunctionsToSync: manifest.serverlessFunctions,
+        serverlessFunctionsToSync: manifest.functions,
         code: manifest.sources,
         workspaceId,
         applicationId: application.id,
@@ -158,7 +158,7 @@ export class ApplicationSyncService {
 
     let serverlessFunctionLayerId = application.serverlessFunctionLayerId;
 
-    if (manifest.serverlessFunctions.length > 0) {
+    if (manifest.functions.length > 0) {
       if (!isDefined(serverlessFunctionLayerId)) {
         serverlessFunctionLayerId = (
           await this.serverlessFunctionLayerService.create(