add requirements.txt so nixpacks can build a standalone python env

requirements.txt

@@ -0,0 +1,28 @@
+# Shared runtime deps for both SREBOT and TSSBOT.
+# Both bots run on a single venv at BOTS/SHARED/.venv (built from this file)
+# and import shared utilities from BOTS/SHARED/. TSSBOT's deps are a subset of
+# SREBOT's, so this is the union of both.
+discord.py>=2.4.0,<3.0.0
+requests>=2.32.3,<3.0.0
+beautifulsoup4>=4.12.3,<5.0.0
+lxml>=5.0.0
+zstandard
+msgpack>=1.0.0,<2.0.0
+lz4==4.3.3
+aiofiles
+aiohttp
+aiohttp-socks
+websockets>=13.0
+aiosqlite
+deepl
+python-dotenv>=1.0.0
+fastapi>=0.104.0
+uvicorn>=0.24.0
+flask>=2.0.0
+Pillow>=10.0.0
+WtFileUtils
+dotenv
+numpy
+wcwidth
+fontTools
+matplotlib