feat(phase-0): scaffold backend + web + docker + DB schema

- docker-compose.yml: timescaledb-ha (timescaledb 2.27 + vectorscale + pgvector + pgai)
  + backend (FastAPI, CUDA 12.1) + web (Next.js 14)
- docker-compose.gpu.yml: GPU profile overlay for RTX 3070 Ti
- build.bat: Windows bootstrap, auto-detects nvidia-smi and selects GPU/CPU compose
- backend: Dockerfile, pyproject.toml, FastAPI skeleton with /health and /health/db
- DB migration 001_init.sql: symbols (with trigram search), ohlcv_daily/1m (hypertables),
  macro_daily, trading_value_daily, news (vector embedding), predictions
  (with user_triggered flag for on-demand UX), prediction_outcomes, model_performance
- web: Next.js 14 + Tailwind + lightweight-charts placeholder
- README: KIS/DART/HuggingFace token issuance guides + 10 seed tickers + run instructions

.gitignore

@@ -0,0 +1,40 @@
+# Env / secrets
+.env
+.env.local
+.env.*.local
+
+# Python
+__pycache__/
+*.py[cod]
+*.pyo
+.Python
+.venv/
+venv/
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+*.egg-info/
+dist/
+build/
+
+# Models / artifacts (downloaded HF caches, trained LGBM)
+backend/artifacts/
+backend/.cache/
+.huggingface/
+
+# Node
+node_modules/
+.next/
+out/
+*.tsbuildinfo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Docker volumes mounted locally
+postgres_data/
+
+# Logs
+*.log
+logs/