💥 Complete QDMI migration

[denialhaag]

Description

🤖 AI text below 🤖

Backports the following QDMI changes to v3.x:

• 💥 Complete the FoMaC-to-QDMI migration #2115
• 💥 Remove the legacy circuit surface for v4 #2288
• ✨ Expose ordered shots from the DDSIM QDMI device #2368
• 💥 Use native Qiskit primitives for QDMI #2358
• ⚡ Submit PennyLane QDMI jobs concurrently #2349
• 📝 Document one QDMI device ID per contended Slurm resource #2190

These changes complete the FoMaC-to-QDMI naming migration, harden QDMI result handling, expose ordered shots from the DDSIM device, replace QDMI-specific Qiskit primitives with native primitives, raise the minimum Qiskit version to 2.1, submit PennyLane QDMI jobs concurrently, and document device selection for Slurm resources.

For #2288, this backport includes only the QDMI result handling that applies to v3.x. It retains the legacy circuit and OpenQASM surface and the DDSIM device's existing importer, without introducing an MLIR or LLVM dependency.

AI notice

This PR and its contents were created with the assistance of GPT-5.6 Sol via Codex.

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.
• I have updated the documentation to reflect these changes.
• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• I have added migration instructions to the upgrade guide (if needed).
• 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

❌ Patch coverage is 95.76271% with 10 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/qdmi/Client.cpp	60.0%	6 Missing ⚠️
include/mqt-core/qdmi/Client.hpp	93.7%	1 Missing ⚠️
python/mqt/core/plugins/pennylane/device.py	96.8%	1 Missing ⚠️
python/mqt/core/plugins/qiskit/job.py	98.5%	1 Missing ⚠️
src/dd/Simulation.cpp	94.4%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[denialhaag]

@burgholzer, this is arguably the busiest PR and also needed a bit more care than more-or-less straightforward cherry-picking. Let me know if I should break this up further to make it easier to review!

[burgholzer]

Reviewed all the changes here. Looks pretty reasonable to me 🙌