Add test suite and fix configuration for Python 3.12

- Add AGENTS.md with coding guidelines for AI agents
- Add comprehensive unit tests for Binance adapter (mocked)
- Add integration tests for Binance testnet connectivity
- Fix pydantic-settings v2 compatibility for nested settings
- Fix MarginType enum to handle lowercase API responses
- Update Python requirement to 3.12+ (pandas-ta dependency)
- Update ruff config to new lint section format
- Update PLAN.md to reflect completed milestones 1.1-1.3

32 tests passing with 81% coverage

pyproject.toml

@@ -8,7 +8,7 @@ version = "0.1.0"
 description = "Automated crypto trading system with regime detection, multi-strategy allocation, and risk management"
 readme = "README.md"
 license = "MIT"
-requires-python = ">=3.11"
+requires-python = ">=3.12"
 authors = [
     { name = "TradeFinder Team" }
 ]
@@ -17,8 +17,8 @@ classifiers = [
     "Development Status :: 3 - Alpha",
     "Intended Audience :: Developers",
     "License :: OSI Approved :: MIT License",
-    "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
 ]
 
 dependencies = [
@@ -91,8 +91,10 @@ Source = "https://github.com/owner/tradefinder"
 packages = ["src/tradefinder"]
 
 [tool.ruff]
-target-version = "py311"
+target-version = "py312"
 line-length = 100
+
+[tool.ruff.lint]
 select = [
     "E",   # pycodestyle errors
     "W",   # pycodestyle warnings
@@ -107,11 +109,11 @@ ignore = [
     "B008",  # do not perform function calls in argument defaults
 ]
 
-[tool.ruff.isort]
+[tool.ruff.lint.isort]
 known-first-party = ["tradefinder"]
 
 [tool.mypy]
-python_version = "3.11"
+python_version = "3.12"
 strict = true
 warn_return_any = true
 warn_unused_configs = true
@@ -121,3 +123,6 @@ plugins = ["pydantic.mypy"]
 asyncio_mode = "auto"
 testpaths = ["tests"]
 addopts = "-v --cov=tradefinder --cov-report=term-missing"
+markers = [
+    "integration: marks tests as integration tests (require testnet API keys)",
+]