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

uv.lock

@@ -259,9 +259,10 @@ wheels = [
 
 [[package]]
 name = "fastapi-traffic"
-version = "0.1.0"
+version = "0.2.0"
 source = { editable = "." }
 dependencies = [
+    { name = "pydantic" },
     { name = "starlette" },
 ]
 
@@ -304,6 +305,7 @@ requires-dist = [
     { name = "fastapi", marker = "extra == 'dev'", specifier = ">=0.100.0" },
     { name = "fastapi", marker = "extra == 'fastapi'", specifier = ">=0.100.0" },
     { name = "httpx", marker = "extra == 'dev'", specifier = ">=0.27.0" },
+    { name = "pydantic", specifier = ">=2.0" },
     { name = "pyright", marker = "extra == 'dev'", specifier = ">=1.1.350" },
     { name = "pytest", marker = "extra == 'dev'", specifier = ">=8.0.0" },
     { name = "pytest-asyncio", marker = "extra == 'dev'", specifier = ">=0.23.0" },