test: replace ad-hoc fake client script with pytest suite

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "linuxawesomebot"
 version = "0.1.0"
-description = "Add your description here"
+description = "OneBot 11 Linux monitoring bot: power/CPU/memory/temps with high-load alerts"
 readme = "README.md"
 authors = [
     { name = "snowy-yang", email = "102860110+snowy-yang@users.noreply.github.com" }
@@ -12,9 +12,8 @@ dependencies = [
     "psutil>=7.2.2",
 ]
 
-[project.scripts]
-linuxawesomebot = "linuxawesomebot:main"
-
-[build-system]
-requires = ["uv_build>=0.12.12,<0.13.0"]
-build-backend = "uv_build"
+[dependency-groups]
+dev = [
+    "pytest>=9.1.1",
+    "pytest-asyncio>=1.4.0",
+]