✨ Add Dynamic QFT benchmark

[inesalonsoo]

Description

Adds an implementation of the dynamic_qft benchmark. In this approach, we use mid-circuit measurements and classical feed-forward loops. The design includes a reversed loop progression (reversed(range(num_qubits))) to resolve the bit-reversal mapping and bypass traditional SWAP gate overhead.

Note to Maintainers: I'm fully aware PR #918 is ahead, but I wanted to submit this layout anyway as a personal statement of practice and an opportunity to engage with the Munich Quantum Toolkit codebase.

Fixes #798

Checklist

• [x ] The pull request only contains commits that are focused and relevant to this change.
• [ x] I have added appropriate tests that cover the new/changed functionality.
• [ x] I have updated the documentation to reflect these changes.
• [ x] I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• [ x] I have added migration instructions to the upgrade guide (if needed).
• [ x] The changes follow the project's style guidelines and introduce no new warnings.
• [ x] The changes are fully tested and pass the CI checks.
• [ x] I have reviewed my own code changes.

If PR contains AI-assisted content:

• [x ] I have disclosed the use of AI tools in the PR description as per our AI Usage Guidelines.
• [x ] I confirm that I have personally reviewed and understood all AI-generated content, and accept full responsibility for it.
• Assisted-by: Gemini AI

##Verification
I executed local testing successfully inside a local Windows PowerShell virtual environment using the following validation stack:

Set local environment pathing

$env:PYTHONPATH="src"

Execute isolated structural verification tests

python -m pytest tests/test_bench.py::test_dynamic_qft_circuit_structure -v

Output: 4 passed in 5.44s (distributed via xdist)

Verify code styling guidelines

python -m ruff check src/mqt/bench/benchmarks/dynamic_qft.py tests/test_bench.py
python -m ruff format --check src/mqt/bench/benchmarks/dynamic_qft.py tests/test_bench.py

[flowerthrower]

Thank you for your initial draft. I left a few comments. Ideally this benchmark mirrors the original QFT as closely as possible, so any user not familiar with the dynamic version can easily see the correspondence.

[flowerthrower]

This is a really short and simple function. No need for helper functions.

[flowerthrower]

To make it more intutive for other users, could you rename the cl. register and mirror exactly the register associations in the QFT version in. You may inspect the QFT circuit like this.

from mqt.bench import get_benchmark, BenchmarkLevel

# original qft benchmark
circ = get_benchmark("qft", BenchmarkLevel.ALG, circuit_size=4)
circ.decompose().draw("mpl", fold=-1)