Create abstract client steps infrastracture to externalize the ap modules client configurations

[alfonso-noriega]

WHY are these changes introduced?

This introduces a new client-side build pipeline system to replace the existing buildConfig approach for extensions. The current system is limited and doesn't provide enough flexibility for complex build scenarios.

WHAT is this pull request doing?

• Adds a new ClientSteps interface that defines build steps as configuration objects with execution handled separately
• Introduces BuildContext to pass data through the step pipeline and store results
• Implements step executors for build_function, build_theme, bundle_theme, and bundle_ui operations
• Adds an include_assets step type with support for pattern-based and config-key-based file inclusions
• Updates ExtensionSpecification to include optional clientSteps field alongside existing buildConfig
• Modifies buildForBundle method to handle app config extensions differently by using the extension UID as the output path
• Adds null coalescing operators to prevent undefined errors when filePatterns and ignoredFilePatterns are not defined
• Includes comprehensive test coverage for the new client steps system

How to test your changes?

1. Create an extension that uses the new clientSteps configuration
2. Run the build process and verify that steps execute in sequence
3. Test the include_assets step with both pattern and configKey inclusion types
4. Verify that error handling works correctly with continueOnError flag
5. Ensure existing extensions using buildConfig continue to work unchanged

Measuring impact

How do we know this change was effective? Please choose one:

• n/a - this doesn't need measurement, e.g. a linting rule or a bug-fix

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes

[alfonso-noriega]

• Add client steps implementation to support existing functionalities #6966 : 2 dependent PRs (#6867 , #6941 )
• Create abstract client steps infrastracture to externalize the ap modules client configurations #6965 👈 (View in Graphite)
• main

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[github-actions]

We detected some changes at packages/*/src and there are no updates in the .changeset.
If the changes are user-facing, run pnpm changeset add to track your changes and include them in the next release CHANGELOG.

Caution

DO NOT create changesets for features which you do not wish to be included in the public changelog of the next CLI release.

[binks-code-reviewer]

⚠️ Findings outside the diff

These findings are in files not modified by this PR and cannot be posted as inline comments.

---

packages/app/src/cli/services/build/client-steps.integration.test.ts:168 — Integration tests assert copying behavior but no implementation exists

The integration test calls executeStep with type: 'include_assets' and asserts files were copied into outputDir, but the router currently throws “not yet implemented” for include_assets, so this test should fail consistently.

Evidence:

await executeStep({ ..., type: 'include_assets', ... }, context)
...
expect(await fileExists(joinPath(outputDir, 'logo.png'))).toBe(true)

Impact:

• PR should fail CI (or indicates these tests aren’t running).
• Confirms the core feature is incomplete.

[binks-code-reviewer]

🤖 Code Review · #projects-dev-ai for questions
React with 👍/👎 or reply — all feedback helps improve the agent.

✅ Complete - No issues

📋 History

❌ Failed → ❌ Failed → ❌ Failed → ✅ 2 findings → ✅ No issues → ❌ Failed → ❌ Failed → ✅ No issues → ✅ No issues

[binks-code-reviewer]

⚠️ Findings outside the diff

These findings are in files not modified by this PR and cannot be posted as inline comments.

---

packages/app/src/cli/models/extensions/extension-instance.ts:369 — New build mode 'hosted_app_home' is added to the type but not handled in build switch

BuildConfig.mode includes 'hosted_app_home', but ExtensionInstance.build() does not handle it. The extension may not be built, producing missing artifacts.

Impact: Specs setting mode=hosted_app_home can lead to deploy failures or missing runtime resources.

[isaacroldan]

use joinPath in all of these

[isaacroldan]

just a minor comment