refactor: rewrite to CoinHunter V2 flat architecture

Replace the V1 commands/services split with a flat, direct architecture:
- cli.py dispatches directly to service functions
- New services: account, market, trade, opportunity
- Thin Binance wrappers: spot_client, um_futures_client
- Add audit logging, runtime paths, and TOML config
- Remove legacy V1 code: commands/, precheck, review engine, smart executor
- Add ruff + mypy toolchain and fix edge cases in trade params

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/coinhunter/config.py

@@ -0,0 +1,132 @@
+"""Configuration and secret loading for CoinHunter V2."""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+from typing import Any
+
+from .runtime import RuntimePaths, ensure_runtime_dirs, get_runtime_paths
+
+try:
+    import tomllib
+except ModuleNotFoundError:  # pragma: no cover
+    import tomli as tomllib
+
+
+DEFAULT_CONFIG = """[runtime]
+timezone = "Asia/Shanghai"
+log_dir = "logs"
+output_format = "json"
+
+[binance]
+spot_base_url = "https://api.binance.com"
+futures_base_url = "https://fapi.binance.com"
+recv_window = 5000
+
+[market]
+default_quote = "USDT"
+universe_allowlist = []
+universe_denylist = []
+
+[trading]
+spot_enabled = true
+futures_enabled = true
+dry_run_default = false
+dust_usdt_threshold = 10.0
+
+[opportunity]
+min_quote_volume = 1000000.0
+top_n = 10
+scan_limit = 50
+ignore_dust = true
+lookback_intervals = ["1h", "4h", "1d"]
+
+[opportunity.weights]
+trend = 1.0
+momentum = 1.0
+breakout = 0.8
+volume = 0.7
+volatility_penalty = 0.5
+position_concentration_penalty = 0.6
+"""
+
+DEFAULT_ENV = "BINANCE_API_KEY=\nBINANCE_API_SECRET=\n"
+
+
+def _permission_denied_message(paths: RuntimePaths, exc: PermissionError) -> RuntimeError:
+    return RuntimeError(
+        "Unable to initialize CoinHunter runtime files because the target directory is not writable: "
+        f"{paths.root}. Set COINHUNTER_HOME to a writable directory or rerun with permissions that can write there. "
+        f"Original error: {exc}"
+    )
+
+
+def ensure_init_files(paths: RuntimePaths | None = None, *, force: bool = False) -> dict[str, Any]:
+    paths = paths or get_runtime_paths()
+    try:
+        ensure_runtime_dirs(paths)
+    except PermissionError as exc:
+        raise _permission_denied_message(paths, exc) from exc
+    created: list[str] = []
+    updated: list[str] = []
+
+    for path, content in ((paths.config_file, DEFAULT_CONFIG), (paths.env_file, DEFAULT_ENV)):
+        if force or not path.exists():
+            try:
+                path.write_text(content, encoding="utf-8")
+            except PermissionError as exc:
+                raise _permission_denied_message(paths, exc) from exc
+            (updated if force and path.exists() else created).append(str(path))
+    return {
+        "root": str(paths.root),
+        "config_file": str(paths.config_file),
+        "env_file": str(paths.env_file),
+        "logs_dir": str(paths.logs_dir),
+        "created_or_updated": created + updated,
+        "force": force,
+    }
+
+
+def load_config(paths: RuntimePaths | None = None) -> dict[str, Any]:
+    paths = paths or get_runtime_paths()
+    if not paths.config_file.exists():
+        raise RuntimeError(f"Missing config file at {paths.config_file}. Run `coinhunter init` first.")
+    return tomllib.loads(paths.config_file.read_text(encoding="utf-8"))  # type: ignore[no-any-return]
+
+
+def load_env_file(paths: RuntimePaths | None = None) -> dict[str, str]:
+    paths = paths or get_runtime_paths()
+    loaded: dict[str, str] = {}
+    if not paths.env_file.exists():
+        return loaded
+    for raw_line in paths.env_file.read_text(encoding="utf-8").splitlines():
+        line = raw_line.strip()
+        if not line or line.startswith("#") or "=" not in line:
+            continue
+        key, value = line.split("=", 1)
+        key = key.strip()
+        value = value.strip()
+        loaded[key] = value
+        os.environ[key] = value
+    return loaded
+
+
+def get_binance_credentials(paths: RuntimePaths | None = None) -> dict[str, str]:
+    load_env_file(paths)
+    api_key = os.getenv("BINANCE_API_KEY", "").strip()
+    api_secret = os.getenv("BINANCE_API_SECRET", "").strip()
+    if not api_key or not api_secret:
+        runtime_paths = paths or get_runtime_paths()
+        raise RuntimeError(
+            "Missing BINANCE_API_KEY or BINANCE_API_SECRET. "
+            f"Populate {runtime_paths.env_file} or export them in the environment."
+        )
+    return {"api_key": api_key, "api_secret": api_secret}
+
+
+def resolve_log_dir(config: dict[str, Any], paths: RuntimePaths | None = None) -> Path:
+    paths = paths or get_runtime_paths()
+    raw = config.get("runtime", {}).get("log_dir", "logs")
+    value = Path(raw).expanduser()
+    return value if value.is_absolute() else paths.root / value