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>

pyproject.toml

@@ -4,20 +4,26 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "coinhunter"
-version = "1.0.0"
-description = "CoinHunter trading CLI with user runtime data in ~/.coinhunter"
+version = "2.0.0"
+description = "Binance-first trading CLI for balances, market data, opportunity scanning, and execution."
 readme = "README.md"
 license = {text = "MIT"}
 requires-python = ">=3.10"
 dependencies = [
-  "ccxt>=4.4.0"
+  "binance-connector>=3.9.0",
+  "binance-futures-connector>=4.1.0",
+  "tomli>=2.0.1; python_version < '3.11'",
 ]
 authors = [
   {name = "Tacit Lab", email = "ouyangcarlos@gmail.com"}
 ]
 
 [project.optional-dependencies]
-dev = ["pytest>=8.0", "ruff>=0.4.0", "mypy>=1.0"]
+dev = [
+  "pytest>=8.0",
+  "ruff>=0.5.0",
+  "mypy>=1.10.0",
+]
 
 [project.scripts]
 coinhunter = "coinhunter.cli:main"
@@ -28,16 +34,24 @@ package-dir = {"" = "src"}
 [tool.setuptools.packages.find]
 where = ["src"]
 
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+
 [tool.ruff]
-line-length = 120
 target-version = "py310"
+line-length = 120
 
 [tool.ruff.lint]
-select = ["E", "F", "W", "I"]
+select = ["E", "F", "I", "UP", "W"]
 ignore = ["E501"]
 
+[tool.ruff.lint.pydocstyle]
+convention = "google"
+
 [tool.mypy]
 python_version = "3.10"
 warn_return_any = true
 warn_unused_configs = true
+disallow_untyped_defs = true
 ignore_missing_imports = true
+exclude = [".venv", "build"]