[subhk]

Fixes remaining transform and gradient edge cases: tiny axis-angle rotations, real-valued vector coefficients, rotation normalization and saved AD inputs, and distributed local evaluation. Latitude calls keep vector outputs at nphi=1, complex MPI evaluation respects :quad scaling, and turbo Laplacians clear excluded orders. Unsupported permuted PencilArray layouts and unsafe Robert-form analysis at nonzero-weight poles now fail before returning incorrect results.

Removes the remaining obsolete SHTns capability contract and stale documentation/changelog references while retaining numerical fixture comparisons. Refreshes the documentation home page, example gallery and figures, architecture/performance guides, and REPL displays for public configuration, plan, and rotation types.