feat: migrate to poetry for dependency management and project configuration

- Added pyproject.toml for project metadata and dependencies.
- Removed requirements.txt as dependencies are now managed by poetry.
- Deleted setup.py as it is no longer needed with poetry.

pyproject.toml

@@ -0,0 +1,24 @@
+[project]
+name = "pyspapi"
+version = "3.3.0"
+description = "API wrapper for SP servers written in Python."
+readme = "README.rst"
+license = { text = "MIT" }
+authors = [{ name = "deesiigneer", email = "xdeesiigneerx@gmail.com" }]
+requires-python = ">=3.12,<3.15"
+dependencies = ["aiohttp>=3.9,<4.0"]
+
+[project.urls]
+Homepage = "https://pyspapi.deesiigneer.ru"
+Documentation = "https://pyspapi.readthedocs.org"
+Repository = "https://github.com/deesiigneer/pyspapi"
+"Issue Tracker" = "https://github.com/deesiigneer/pyspapi/issues"
+Discord = "https://discord.com/invite/VbyHaKRAaN"
+
+[dependency-groups]
+dev = ["ruff>=0.14,<0.15", "toml-sort>=0.24,<0.25"]
+docs = ["sphinx>=7,<9", "sphinx-autobuild (>=2025.8.25,<2026.0.0)", "pydata-sphinx-theme (>=0.16.1,<0.17.0)"]
+
+[build-system]
+requires = ["poetry-core>=2.0.0,<3.0.0"]
+build-backend = "poetry.core.masonry.api"