feat(publish): add PyPI publish workflow, CLI command, parser integration, and tests

* Introduce publish action with PyPI target detection via MIRRORS
* Resolve version from SemVer git tags on HEAD
* Support preview mode and non-interactive CI usage
* Build and upload artifacts using build + twine with token resolution
* Add CLI wiring (dispatch, command handler, parser)
* Add E2E publish help tests for pkgmgr and nix run
* Add integration tests for publish preview and mirror handling
* Add unit tests for git tag parsing, PyPI URL parsing, workflow preview, and CLI handler
* Clean up dispatch and parser structure while integrating publish

https://chatgpt.com/share/693f0f00-af68-800f-8846-193dca69bd2e

tests/unit/pkgmgr/actions/publish/test_git_tags.py

@@ -0,0 +1,20 @@
+
+import unittest
+from unittest.mock import patch
+
+from pkgmgr.actions.publish.git_tags import head_semver_tags
+
+
+class TestHeadSemverTags(unittest.TestCase):
+    @patch("pkgmgr.actions.publish.git_tags.run_git")
+    def test_no_tags(self, mock_run_git):
+        mock_run_git.return_value = ""
+        self.assertEqual(head_semver_tags(), [])
+
+    @patch("pkgmgr.actions.publish.git_tags.run_git")
+    def test_filters_and_sorts_semver(self, mock_run_git):
+        mock_run_git.return_value = "v1.0.0\nv2.0.0\nfoo\n"
+        self.assertEqual(
+            head_semver_tags(),
+            ["v1.0.0", "v2.0.0"],
+        )

tests/unit/pkgmgr/actions/publish/test_pypi_url.py

@@ -0,0 +1,13 @@
+
+import unittest
+from pkgmgr.actions.publish.pypi_url import parse_pypi_project_url
+
+
+class TestParsePyPIUrl(unittest.TestCase):
+    def test_valid_pypi_url(self):
+        t = parse_pypi_project_url("https://pypi.org/project/example/")
+        self.assertIsNotNone(t)
+        self.assertEqual(t.project, "example")
+
+    def test_invalid_url(self):
+        self.assertIsNone(parse_pypi_project_url("https://example.com/foo"))

tests/unit/pkgmgr/actions/publish/test_workflow_preview.py

@@ -0,0 +1,21 @@
+
+import unittest
+from unittest.mock import patch
+
+from pkgmgr.actions.publish.workflow import publish
+
+
+class TestPublishWorkflowPreview(unittest.TestCase):
+    @patch("pkgmgr.actions.publish.workflow.read_mirrors_file")
+    @patch("pkgmgr.actions.publish.workflow.head_semver_tags")
+    def test_preview_does_not_build(self, mock_tags, mock_mirrors):
+        mock_mirrors.return_value = {
+            "pypi": "https://pypi.org/project/example/"
+        }
+        mock_tags.return_value = ["v1.0.0"]
+
+        publish(
+            repo={},
+            repo_dir=".",
+            preview=True,
+        )

tests/unit/pkgmgr/cli/commands/test_publish.py

@@ -0,0 +1,12 @@
+
+import unittest
+from unittest.mock import patch
+
+from pkgmgr.cli.commands.publish import handle_publish
+
+
+class TestHandlePublish(unittest.TestCase):
+    @patch("pkgmgr.cli.commands.publish.publish")
+    def test_no_selected_repos(self, mock_publish):
+        handle_publish(args=object(), ctx=None, selected=[])
+        mock_publish.assert_not_called()