fix(v12): resolve 6 defects from v11 audit (F-NEW-6, S-NEW-5, M-NEW-5/6, MI-NEW-4/5/6)

fix(v11): resolve remaining 5 defects (S-NEW-1/2, M-NEW-2/3, MI-NEW-1)

fix(v9): resolve 3 fatal + 1 serious + 1 moderate defects from external audit

fix: v5 remove empty tokenizer.json, unify think tokens, integrate tokenizer into training pipeline

chore: replace author real name with GitHub username

feat: 初始化 Fusion 项目 - 六边形开源大模型