v0.13.0 — LLM optimizes all four Kconfig dimensions

Single-axis (tristate trim) → four-axis (modules + choices + toggles + tunables) LLM-driven optimization. Workload-aware via --workload (auto-detected). autokernel build --localmodconfig cuts module count 6000→250 from host's lsmod.

autokernel propose <snap> --dimension=all --workload=desktop \
    --kernel-source=/path/to/linux

635 tests, ~4s. Live boot-test: 0.2s under virtme-ng.