1212bd0e

By: Valentin Hirschi <valentin.hirschi@gmail.com>

Recognize independent massless bubbles in recursive boundaries

Use FeynKit's exact affine mappings to recognize two unit-power massless
bubbles and reuse the existing one-loop Gamma terminal. Single-mass E1
boundaries then avoid recursive AMF reduction while unsupported families
retain their existing fallback.

Observe peeled-child visits through TerminalProvider in the complex-mass
regression, since an exact child terminal need not call the reducer.

Validation: eight banana unit tests, all five nonignored single-mass tests,
and 24 original/candidate/Mathematica comparisons, including fresh high
precision factors and independent old recursive values. The long ignored
Laurent test was not run.