Add Azure CLI authentication task breakdown AB#1694265

[ayeshurun]

ADO Work Item: AB#1694265

Summary

• add seven direct child implementation Tasks under User Story 1694265
• document repo-scoped scope, dependencies, acceptance criteria, and design references
• add the generated task index and link the tasks from the design and implementation plan

ADO Tasks

• AB#2216015 — shared executor and authentication coordinator
• AB#2216016 — Azure CLI provider and explicit login
• AB#2216017 — identity binding and atomic state
• AB#2216018 — shared chooser and continuation
• AB#2216019 — status, errors, and logout
• AB#2216020 — HTTP, SDK, deploy, and batch integration
• AB#2216021 — release matrix, docs, telemetry, and Skills pilot

All task markdown records have been synchronized to Power BI / Trident.