Add AIP progress tracker example DAG for common.ai provider

[vikramkoka]

Demonstrates LLMOperator with Dynamic Task Mapping, structured output, UsageLimits, and HITL approval — no framework dependency.

The DAG gathers AIP specs from the Confluence wiki and searches GitHub for related PRs, then uses an LLM to assess each AIP's progress and synthesize a cross-AIP report for maintainer review.

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Was generative AI tooling used to co-author this PR?

• [x ] Yes (please specify the tool below)

Generated-by: [Claude] following the guidelines

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• Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
• For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
• When adding dependency, check compliance with the ASF 3rd Party License Policy.
• For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.