feat(cli): Replace mcp run with click CLI and runtime options

BREAKING CHANGE: FASTMCP_-prefixed env vars have been replaced by CLI
arguments. Refer to the README for updated usage.

Usage: python -m nextcloud_mcp_server.app [OPTIONS]

Options:
  -h, --host TEXT
  -p, --port INTEGER
  -w, --workers INTEGER
  -r, --reload
  --log-level [critical|error|warning|info|debug|trace]
  -t, --transport [sse|streamable-http]
  -e, --enable-app [notes|tables|webdav|calendar|contacts]
                                  Enable specific Nextcloud app APIs. Can be
                                  specified multiple times. If not specified,
                                  all apps are enabled.
  --help                          Show this message and exit.

pyproject.toml

@@ -14,6 +14,7 @@ dependencies = [
     "icalendar (>=6.0.0,<7.0.0)",
     "pythonvcard4>=0.2.0",
     "pydantic>=2.11.4",
+    "click>=8.1.8",
 ]
 
 [tool.pytest.ini_options]
@@ -48,3 +49,6 @@ dev = [
     "pytest-cov>=6.1.1",
     "ruff>=0.11.13",
 ]
+
+[project.scripts]
+nextcloud-mcp-server = "nextcloud_mcp_server.app:run"