✨ Add the quantum-ipo pipeline scheduling the interprocedural passes

[DRovara]

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Description

Last of the stack replacing #1970. Builds on #2200. Once this lands, #1970 can be closed as superseded.

populateQuantumIPOPipeline runs the four passes in the order they compose, registered as the quantum-ipo pipeline. Commutation runs twice because it can expose further cancellations. The passes stay individually registered, so a caller assembling its own pipeline can pick only the ones it wants.

test_qco_quantum_ipo.cpp now holds only the scenarios that need more than one pass; everything about a single pass lives in that pass's own suite. This is the review comment on the original PR actioned across the whole series — previously most per-pass cases ran through the full pipeline, which made it hard to tell which stage established a result and let one stage mask a regression in another.

Splitting them found a real instance of exactly that: a promotion case in #2198 was passing only because the preceding pass's greedy pattern driver incidentally folded the IR first.

The changelog entry for the whole series now lives in the infrastructure PR #2194.

Testing

Three cross-stage cases live here; the complete optimization suite passes all 246 tests.

AI assistance

Code and this description were produced with Claude Code (Opus 5) and Codex, acting on my instructions and within the scope I authorized.

Checklist

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
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• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
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• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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