v0.5.26 — Expanded model menu (CPU 9 options, GPU reordered)

Setup wizard model selection overhaul:

CPU-only path now shows 9 models ordered by speed (fastest first), with phi4:3.8b clearly marked as recommended for best RAG reasoning. Adds mistral:7b, llama3.1:8b, and openhermes:7b to the CPU list with RAM warnings.

GPU path reordered: phi4:3.8b first (best reasoning per GB), then mistral:7b, openhermes:7b (full tag), llama3.1:8b, then larger models.

openhermes model now uses the explicit tag openhermes:7b-mistral-v2-q4_K_M.