By: ValentinHirschi <valentin.hirschi@gmail.com>
cli: address review of the hand-written DOT preparation - Expand single-vertex fermion lines (bare gamma/gamma5/projm/projp/gamma0 between two spinors) and loop vectors carrying an open Lorentz index; each index is summed with the metric across lines and vectors. Validated against slashed-momentum trace projectors for the e- mu- vertex correction and vacuum polarization. A leftover spinor structure is named when every fermion leg is bound. - Check chain_in/chain_out: (out, in) factors are transposed, anything else is rejected. - Join open color slots automatically only when they belong to two distinct colored external legs; dangling indices stay an error. - Derive the generator's graph factors in ninjars-graph's prepare_dot, so every DOT path (prepare, reduce, numerator-bench, pipeline-bench, ...) shares the rule; PreparedIntegrand records the factors and whether they were applied. Report open fermion lines and warn when two or more leave the external-ordering sign underived; correct the docs on that sign. - The fast engine also reports repeated_propagator, from an exact check of the prepared sample. - Library test of the repeated-propagator donor branch in every precision, with and without a supplied S-matrix; update the reference-codegen test to the earlier rejection; record color_dimension_invariants in the JSON. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>