Crypto trading bot: engine, brokers, backtester, dashboard, deploy

FastAPI backend with a single-strategy async engine, paper and Binance
brokers, pure-python indicators, a backtester that shares the engine's
portfolio math, and a Vue dashboard with a live WebSocket feed. Adds the
Gitea Actions CI/CD workflow that deploys to Traefik via docker_default.

backend/app/config.py

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+from __future__ import annotations
+
+from functools import lru_cache
+from pathlib import Path
+
+from pydantic import field_validator
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+DATA_DIR = REPO_ROOT / "data"
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(
+        env_file=(REPO_ROOT / ".env", ".env"),
+        env_file_encoding="utf-8",
+        extra="ignore",
+    )
+
+    app_name: str = "Crypto Trader"
+    env: str = "dev"
+    host: str = "0.0.0.0"
+    port: int = 8000
+
+    database_url: str = "sqlite:///./data/trader.db"
+
+    mode: str = "paper"
+    exchange: str = "binance"
+    symbol: str = "BTC/USDT"
+    timeframe: str = "1m"
+    poll_interval: float = 5.0
+    candle_limit: int = 200
+
+    starting_balance: float = 10_000.0
+    fee_bps: float = 10.0
+    slippage_bps: float = 5.0
+
+    exchange_api_key: str = ""
+    exchange_api_secret: str = ""
+    exchange_sandbox: bool = False
+
+    cors_origins: str = "*"
+
+    @field_validator("mode")
+    @classmethod
+    def _validate_mode(cls, value: str) -> str:
+        value = value.lower().strip()
+        if value not in {"paper", "live"}:
+            raise ValueError("mode must be 'paper' or 'live'")
+        return value
+
+    @property
+    def cors_origin_list(self) -> list[str]:
+        return [origin.strip() for origin in self.cors_origins.split(",") if origin.strip()]
+
+    @property
+    def is_live(self) -> bool:
+        return self.mode == "live"
+
+
+@lru_cache
+def get_settings() -> Settings:
+    settings = Settings()
+    DATA_DIR.mkdir(parents=True, exist_ok=True)
+    return settings