chore: scaffold uv project, config, personas, risk, model profiles

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016DvdRZkyCy9NJpHYDdPqmS

.gitignore

@@ -0,0 +1,18 @@
+# secrets
+.env
+
+# python
+.venv/
+__pycache__/
+*.py[cod]
+.pytest_cache/
+.ruff_cache/
+
+# runtime state (keep dirs via .gitkeep, ignore contents)
+state/trading.db
+state/*.db
+state/output/
+state/logs/
+
+# os
+.DS_Store