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>

tests/test_config_runtime.py

@@ -0,0 +1,79 @@
+"""Config and runtime tests."""
+
+from __future__ import annotations
+
+import os
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+from coinhunter.config import ensure_init_files, get_binance_credentials, load_config, load_env_file
+from coinhunter.runtime import get_runtime_paths
+
+
+class ConfigRuntimeTestCase(unittest.TestCase):
+    def test_init_files_created_in_coinhunter_home(self):
+        with tempfile.TemporaryDirectory() as tmp_dir, patch.dict(os.environ, {"COINHUNTER_HOME": str(Path(tmp_dir) / "home")}, clear=False):
+            paths = get_runtime_paths()
+            payload = ensure_init_files(paths)
+            self.assertTrue(paths.config_file.exists())
+            self.assertTrue(paths.env_file.exists())
+            self.assertTrue(paths.logs_dir.exists())
+            self.assertEqual(payload["root"], str(paths.root))
+
+    def test_load_config_and_env(self):
+        with tempfile.TemporaryDirectory() as tmp_dir, patch.dict(
+            os.environ,
+            {"COINHUNTER_HOME": str(Path(tmp_dir) / "home")},
+            clear=False,
+        ):
+            paths = get_runtime_paths()
+            ensure_init_files(paths)
+            paths.env_file.write_text("BINANCE_API_KEY=abc\nBINANCE_API_SECRET=def\n", encoding="utf-8")
+
+            config = load_config(paths)
+            loaded = load_env_file(paths)
+
+            self.assertEqual(config["market"]["default_quote"], "USDT")
+            self.assertEqual(loaded["BINANCE_API_KEY"], "abc")
+            self.assertEqual(os.environ["BINANCE_API_SECRET"], "def")
+
+    def test_env_file_overrides_existing_environment(self):
+        with tempfile.TemporaryDirectory() as tmp_dir, patch.dict(
+            os.environ,
+            {"COINHUNTER_HOME": str(Path(tmp_dir) / "home"), "BINANCE_API_KEY": "old_key"},
+            clear=False,
+        ):
+            paths = get_runtime_paths()
+            ensure_init_files(paths)
+            paths.env_file.write_text("BINANCE_API_KEY=new_key\nBINANCE_API_SECRET=new_secret\n", encoding="utf-8")
+
+            load_env_file(paths)
+
+            self.assertEqual(os.environ["BINANCE_API_KEY"], "new_key")
+            self.assertEqual(os.environ["BINANCE_API_SECRET"], "new_secret")
+
+    def test_missing_credentials_raise(self):
+        with tempfile.TemporaryDirectory() as tmp_dir, patch.dict(
+            os.environ,
+            {"COINHUNTER_HOME": str(Path(tmp_dir) / "home")},
+            clear=False,
+        ):
+            os.environ.pop("BINANCE_API_KEY", None)
+            os.environ.pop("BINANCE_API_SECRET", None)
+            paths = get_runtime_paths()
+            ensure_init_files(paths)
+            with self.assertRaisesRegex(RuntimeError, "Missing BINANCE_API_KEY"):
+                get_binance_credentials(paths)
+
+    def test_permission_error_is_explained(self):
+        with tempfile.TemporaryDirectory() as tmp_dir, patch.dict(
+            os.environ,
+            {"COINHUNTER_HOME": str(Path(tmp_dir) / "home")},
+            clear=False,
+        ):
+            paths = get_runtime_paths()
+            with patch("coinhunter.config.ensure_runtime_dirs", side_effect=PermissionError("no write access")):
+                with self.assertRaisesRegex(RuntimeError, "Set COINHUNTER_HOME to a writable directory"):
+                    ensure_init_files(paths)