Calculates the cyclomatic complexity of a PowerShell script or code block, including both functions and top-level code.

Cyclomatic and cognitive complexity for PowerShell. Cognitive complexity is a faithful port of the SonarSource metric (nesting-aware -- the better signal for "hard to understand"), validated against reference scores. Measures per unit (function/filter + script body) via the PowerShell AST; ships a Test-PSComplexity gate for CI.