Split the worker into a distribution of its own

A cluster or GPU host installs `pip install fluksio-worker` and gets the
agent and the runner, not psycopg, numpy and the MCP SDK. The engine
depends on it as a workspace member, so the file it launches node code
with is the same file a remote worker runs — which is what keeps a node
unable to tell the difference. Copying the two files by hand still works.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

worker/pyproject.toml

@@ -0,0 +1,31 @@
+[project]
+name = "fluksio-worker"
+version = "0.1.0"
+description = "Runs Fluksio nodes on a machine the engine cannot reach"
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = [
+    "websockets>=12",
+]
+
+[project.scripts]
+fluksio-worker = "fluksio_worker.agent:main"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["fluksio_worker"]
+
+[tool.ruff]
+# The engine's config, so both distributions are linted the same way.
+extend = "../backend/pyproject.toml"
+
+[tool.ruff.lint.per-file-ignores]
+# This one takes its own directory off sys.path before the rest of its imports
+# run, which is the whole point of doing it there.
+"fluksio_worker/worker_main.py" = ["E402"]
+# Copied onto another machine it has no logger configured before it tells you
+# the one dependency it is missing.
+"fluksio_worker/agent.py" = ["T201"]