Clarify azure.ai.project ownership across project workflows

## Summary

Make ownership of `azure.ai.project` explicit and consistent across the Azure AI project workflows.

## What to do

- Establish a clear ownership model for project resources.
- Route project-level operations through the project owner instead of individual resource helpers where appropriate.
- Keep initialization, adoption, and managed-resource flows aligned with the same ownership rules.
- Add focused tests for project ownership, resource discovery, and error handling.
- Update user-facing guidance where the ownership model affects behavior.

## Outcome

Project resources have one predictable ownership path, reducing duplicated logic and making future workflow changes safer.

Review the open linked pull request #10030 alongside the issue's initialization, adoption, and managed-resource workflow requirements. Trace the existing project ownership and resource-helper paths, then verify that focused tests cover ownership, resource discovery, and error handling and that user-facing guidance reflects the final ownership model.

Written by the indexing model from the issue text.