Summary

• expose Rust parity for quantics transform wrappers in Julia
• add grouped quantics-grid unfolding and top-level grid exports
• add quantics transform/grid regression tests and refresh the README/PR workflow notes

What changed

• added C bindings and Julia wrappers for multivariable shift/flip/phase, affine, binary-op, and input/output space remapping
• exported DiscretizedGrid, InherentDiscreteGrid, and localdimensions from the top level and added :grouped unfolding support
• added MPS(::SimpleTensorTrain) so high-level quantics transform examples can materialize valid input states
• updated README.md to remove outdated TensorCI examples and document the current quantics APIs
• updated AGENTS.md to require a README review before opening or updating a PR

Validation

• TENSOR4ALL_RS_PATH=/home/shinaoka/tensor4all/tensor4all-rs/.worktrees/feat-quanticstransform-capi julia --startup-file=no --project=/home/shinaoka/tensor4all/Tensor4all.jl /home/shinaoka/tensor4all/Tensor4all.jl/deps/build.jl
• julia --startup-file=no --project=/home/shinaoka/tensor4all/Tensor4all.jl -e 'using Test, Tensor4all; include("/home/shinaoka/tensor4all/Tensor4all.jl/test/test_quanticsgrids.jl"); include("/home/shinaoka/tensor4all/Tensor4all.jl/test/test_quanticstransform.jl")'
• julia --startup-file=no --project=/home/shinaoka/tensor4all/Tensor4all.jl -e 'using Tensor4all; using Tensor4all.SimpleTT; using Tensor4all.TreeTN; using Tensor4all.QuanticsTransform; using Tensor4all.QuanticsGrids: origcoord_to_quantics, quantics_to_origcoord; tt = SimpleTensorTrain([2,3,4], 1.0); @assert tt(0,0,0) == 1.0; @assert Tensor4all.SimpleTT.site_dims(tt) == [2,3,4]; grid = DiscretizedGrid(2, [2,2], [0.0,0.0], [1.0,1.0]; unfolding=:grouped); q = origcoord_to_quantics(grid, [0.25,0.75]); x = quantics_to_origcoord(grid, q); @assert length(q) == 4; @assert x[1] isa Float64; mps = MPS(SimpleTensorTrain([2,2,2], 1.0)); op = shift_operator(3, 1); set_iospaces!(op, mps); shifted = apply(op, mps; method=:naive); @assert length(shifted) == 3; multi = shift_operator_multivar(3, 1, 2, 0); flipped = flip_operator_multivar(3, 2, 1; bc=Open); phase = phase_rotation_operator_multivar(3, pi / 4, 2, 1); aff = affine_operator(3, Int64[1 -1; 1 0; 0 1], ones(Int64, 3, 2), Int64[0,0,0], ones(Int64, 3); bc=[Open, Periodic, Periodic]); println("README snippets ok")'
• T4A_SKIP_HDF5_TESTS=1 julia --startup-file=no --project=/home/shinaoka/tensor4all/Tensor4all.jl /home/shinaoka/tensor4all/Tensor4all.jl/test/runtests.jl