refactor: improve config loader validation with Pydantic schemas

- Replace manual field type validation with Pydantic model schemas
- Add pydantic>=2.0 as core dependency
- Fix sync wrapper in decorator to properly handle rate limiting
- Update pyright settings for stricter type checking
- Fix repository URL in pyproject.toml
- Remove unused main.py
- Update test assertions for new validation error format

fastapi_traffic/core/config.py

@@ -4,7 +4,7 @@ from __future__ import annotations
 
 from collections.abc import Callable
 from dataclasses import dataclass, field
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, TypeAlias
 
 from fastapi_traffic.core.algorithms import Algorithm
 
@@ -14,7 +14,7 @@ if TYPE_CHECKING:
     from fastapi_traffic.backends.base import Backend
 
 
-KeyExtractor = Callable[["Request"], str]
+KeyExtractor: TypeAlias = Callable[["Request"], str]
 
 
 def default_key_extractor(request: Request) -> str:
@@ -55,10 +55,10 @@ class RateLimitConfig:
         if self.limit <= 0:
             msg = "limit must be positive"
             raise ValueError(msg)
-        if self.window_size <= 0:
+        elif self.window_size <= 0:
             msg = "window_size must be positive"
             raise ValueError(msg)
-        if self.cost <= 0:
+        elif self.cost <= 0:
             msg = "cost must be positive"
             raise ValueError(msg)