【代码贡献】新增可复用量子傅里叶变换（QFT）模块

[tokenjunkielabs]

Relates to #13 (2026 本源杯 open-source innovation / code contribution).

Adds a dedicated reusable Quantum Fourier Transform module instead of requiring callers to reach into the generic plugin helper.

• forward and inverse QFT circuit construction
• explicit least-significant-to-most-significant qubit ordering
• optional final swaps with an exposed bit-reversal permutation
• simulator-independent NumPy reference transform defining the phase/order convention
• configured QuantumFourierTransform builder for repeated forward/inverse use
• package-level export, documentation, and runnable circuit example

The implementation follows the existing pyqpanda-algorithm controlled-phase convention while making inverse and output-order semantics explicit.

Per the current contributor workflow, no test run is claimed for this submission.