server: replace requirements.txt with pyproject.toml (use uv)

server/pyproject.toml

@@ -0,0 +1,9 @@
+[project]
+name = "bincio-planner-server"
+version = "0.1.0"
+requires-python = ">=3.11"
+dependencies = [
+    "fastapi>=0.111",
+    "uvicorn[standard]>=0.29",
+    "pydantic>=2.0",
+]

server/requirements.txt

@@ -1,3 +0,0 @@
-fastapi>=0.111
-uvicorn[standard]>=0.29
-pydantic>=2.0