docs: add setup guide and test coverage

tests/test_server_contract.py

@@ -0,0 +1,12 @@
+from __future__ import annotations
+
+from openherbarium_mcp import __version__
+from openherbarium_mcp.server import mcp
+
+
+def test_package_version() -> None:
+    assert __version__ == "0.1.0"
+
+
+def test_fastmcp_server_exists() -> None:
+    assert mcp.name == "OpenHerbarium MCP"