refactor: modernize code quality tooling with Ruff

- Replace black, isort, and flake8 with Ruff (all-in-one linter and formatter)
- Add comprehensive pyproject.toml configuration
- Simplify Makefile code quality targets
- Configure exclusions for venv/.venv in pyproject.toml
- Auto-fix 1,359 linting issues across codebase

Benefits:
- Much faster builds (Ruff is written in Rust)
- Single tool replaces multiple tools
- More comprehensive rule set (UP, B, C4, SIM, PIE, RET, Q)
- All configuration centralized in pyproject.toml
- Better import sorting and formatting consistency

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

models/schema/base.py

@@ -1,4 +1,4 @@
-from typing import Generic, List, TypeVar
+from typing import Generic, TypeVar
 
 from pydantic import BaseModel
 
@@ -8,7 +8,7 @@ T = TypeVar("T")
 class ListResponse(BaseModel, Generic[T]):
     """Generic list response model"""
 
-    items: List[T]
+    items: list[T]
     total: int
     skip: int
     limit: int