Bump nixpkgs and nixpkgs-latest from 2026-05/2026-08 to current
nixos-unstable (2026-09-11); both inputs now resolve to the same rev.
Re-validated every package against the new inputs.
Fallout fixed:
- freetoken: upstream pins torch>=2.11,<2.12 and triton==3.6.0, but the new
nixpkgs only ships torch 2.13 / triton 3.7. Add a nixpkgs-torch211 input
pinned at the previous revision and build freetoken against it, keeping
the CUDA 12.9 / torch 2.11 stack unchanged.
- graphify: nixpkgs' pybloomfilter3 0.7.3 ships sdist metadata that still
says 0.7.2, tripping pythonMetadataCheckPhase; skip that check only.
All 22 packages build and `nix flake check --no-build` passes.
Alexander Miroshnichenko
3f868775af