feat(admin-config-tool): task 1.1 - xceadmin package skeleton

Editable-installable xceadmin package with a real click-group entry
point (zero subcommands yet) and xcecommon as an independently
importable standalone package.

Requirements: 5.4

src/xceadmin/pyproject.toml

@@ -0,0 +1,29 @@
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "xceadmin"
+version = "0.1.0"
+description = "XCE cluster configuration admin CLI (config build / config push)"
+requires-python = ">=3.10"
+dependencies = [
+    "click>=8.0",
+]
+
+# NOT wired into meson (src/meson.build / src/meson.options) — xceadmin is
+# dispatched by src/tools/xce-build.sh's case-statement pattern instead.
+# See .kiro/specs/admin-config-tool/design.md, File Structure Plan.
+
+[project.optional-dependencies]
+test = ["pytest"]
+
+[project.scripts]
+xceadmin = "xceadmin.cli:main"
+
+[tool.setuptools.packages.find]
+where = ["src"]
+include = ["xceadmin*", "xcecommon*"]
+
+[tool.setuptools.package-dir]
+"" = "src"