【代码贡献】新增量子相位估计（QPE）算法模块

[tokenjunkielabs]

Refs #13.

Adds a reusable Quantum Phase Estimation (QPE) module to the PyQPanda3 algorithm package.

What this contributes

• standard counting-register QPE with inverse QFT, following the same register-power convention already used by QAE;
• pluggable eigenstate preparation and unitary construction;
• optional unitary_power(qubits, power) hook so applications with native U^k construction do not need to repeat the base circuit;
• PhaseEstimationResult with dominant phase, bit string, probability, resolution, and the full phase-register distribution;
• phase_to_eigenvalue helper for U = exp(i H t), including centered signed-phase decoding;
• public pyqpanda_alg.QPE export plus Cython-package initializer handling;
• runnable one-qubit 3/8-phase example;
• Chinese and English package documentation.

Source head: f0bd921, directly based on sponsor develop@5f973efccb84bc193157d1ccebe32137e307293b.

No test run is claimed; submission scope is the implementation, package API, documentation, and example.