Fix Azure CLI extension dependency loading and release validation

[Chien Yuan Chang (chienyuanchang)]

Summary

• publish the corrected Azure CLI extension as 0.1.0b2 without changing immutable 0.1.0b1
• make cu-cli-core the sole owner of azure-ai-contentunderstanding>=1.2.0b3 for both cu-cli and az cu
• route client construction and LLM-input rendering through core-owned lazy SDK abstractions
• accept plain result mappings in the core renderer so URL redaction and span remapping remain frontend-neutral
• ban direct CU SDK references and dependency declarations in both frontend source and tests
• make extension loading robust when Azure CLI has already imported the azure.ai namespace
• validate the exact extension/core wheel pair in a clean Azure CLI installation
• run pinned upstream-style azdev lint and style checks in CI and before release
• smoke-test clean wheel installation on Python 3.12 and 3.13
• model the analyzer-copy linter exclusions required by its intentionally descriptive source/destination options

Validation

• complete cu-cli/scripts/ci.sh suite: core, standalone, integration playback, and Azure CLI extension tests
• Ruff and mypy for core, standalone, and extension
• frontend SDK architecture guard
• clean Azure CLI wheel installation and az cu --help
• azdev==0.2.13 wheel linter and source style checks against Azure CLI dev and Azure CLI extensions main
• git diff --check

Included related fixes

• Generate the Azure CLI extension GitHub release notes from the selected HISTORY.rst version section (supersedes Fix Azure CLI extension GitHub release notes #33).
• Preserve long input paths in standalone CLI usage output (supersedes Preserve long paths in usage output #34).
• Prepare cu-cli-core and standalone cu-cli 0.1.0b3 metadata and release notes; the extension remains 0.1.0b2 and requires core 0.1.0b3.