feat(application): platform app build task that runs after build_application across envs

[davidfirst]

Adds a dedicated build task for "platform" apps (apps that bundle other apps' build artifacts), so cross-env ordering can't leave a platform's bundler reading an artifact that hasn't been produced yet.

Why

On a lane with a platform-app (node env) that embeds a frontend-app (react env) and a backend-app (node env), the build pipeline iterates env-by-env. When node env runs first, the platform-app's bundler can't find the frontend-app's app-build artifact because react env hasn't run yet. Toposorting envs by component deps doesn't work — components across envs often form env-level cycles even when component deps are acyclic.

How

• New Application.platform?: boolean opt-in on the app.
• AppsBuildTask gains a shouldRunForApp hook and skips apps where platform === true.
• New PlatformAppsBuildTask extends AppsBuildTask, runs only for platform apps, and declares dependencies: ['teambit.harmony/application:build_application']. The existing toposort in the end location bucket places build_application (every env) ahead of build_platform_application (every env), so by the time the platform task fires, every other env has already emitted its app-bundle artifact.
• DeployTask resolves build metadata from the correct task name based on app.platform.

Test plan

• Run build on a platform lane and confirm the platform's bundler finds upstream app-build artifacts regardless of env iteration order
• Confirm non-platform apps still build and deploy via build_application / deploy_application unchanged
• Platform components: set platform = true on the Platform class to opt in

[Copilot]

Pull request overview

Adds a dedicated build task for “platform” apps (apps that bundle other apps’ build artifacts) so they can reliably run after all envs have completed build_application, avoiding cross-env ordering issues where a platform bundler reads artifacts that don’t exist yet.

Changes:

• Added Application.platform?: boolean opt-in to classify platform apps.
• Updated AppsBuildTask to skip platform apps via a new shouldRunForApp() hook, and introduced PlatformAppsBuildTask that runs only for platform apps and depends on build_application.
• Updated DeployTask to resolve build metadata from build_platform_application when deploying platform apps.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
scopes/harmony/application/deploy.task.ts	Selects build-task results based on app.platform so deploy reads metadata from the correct build task.
scopes/harmony/application/build-platform-application.task.ts	New build task (build_platform_application) that runs after build_application and targets only platform apps.
scopes/harmony/application/build-application.task.ts	Adds shouldRunForApp() and skips apps marked platform === true.
scopes/harmony/application/application.ts	Introduces the platform?: boolean flag on the Application interface with behavior documentation.
scopes/harmony/application/application.main.runtime.ts	Registers the new PlatformAppsBuildTask alongside the existing app build task.