phase 7-8 完成 + warmup 修复 + 产物结构化重组

主要内容：
- Phase 8 PROMOTE: finalist #1 (trial #324) registry 条目，自动生成
- Optuna objective warmup bug 修复 (shared/optimizer/objective.py)
- studies/ 目录按用途重组为 optuna/ + finalists/ + features/ 三层
- reports/ 加入 Optuna 中文 dashboard (5 主图 + 18 slice + 15 contour)
- 新增 PROJECT_GUIDE.md 项目说明文档
- 新增 build_registry_entry.py / build_optuna_dashboard.py / build_feature_datasets.py
- .gitignore: 允许提交 studies/*.db (Optuna DB) 和 reports/*.html (MT5 + dashboard)

.gitignore

@@ -8,8 +8,6 @@ data/
 
 # Run outputs / scratch
 results/
-*.db          # Optuna SQLite studies
-*.htm         # pulled MT5 reports
 
 # Secrets — NEVER commit broker credentials
 .env
@@ -18,3 +16,9 @@ results/
 # OS
 .DS_Store
 Thumbs.db
+
+# NOTE: studies/*.db (Optuna) and reports/*.html (MT5 + dashboard) ARE
+# committed — they're research artifacts, not scratch output. The Optuna DB
+# is the only way to reproduce a finalist; HTML reports are the only ground
+# truth for the Python-vs-MT5 gap analysis.
+