Refactor release helper into actions package and add RPM changelog support

- Move the monolithic pkgmgr/actions/release.py implementation into the
  pkgmgr.actions.release package, splitting concerns into versioning,
  git_ops and files helpers.
- Extend the release orchestration to update Fedora/RPM %changelog
  entries via update_spec_changelog(), reusing the same effective
  release message as for CHANGELOG.md and debian/changelog.
- Wire the new update_spec_changelog() helper into _release_impl() so
  every release keeps project, Debian and RPM metadata in sync.
- Add unit tests for update_spec_changelog() and for the updated release
  orchestration behaviour in preview and real modes.
- Remove the deprecated pkgmgr/actions/release.py module.

See ChatGPT discussion: https://chatgpt.com/share/6938368e-0940-800f-92d3-f2ccfddab794

tests/unit/pkgmgr/actions/release/test_release_orchestration.py

@@ -19,6 +19,7 @@ class TestReleaseOrchestration(unittest.TestCase):
             patch("pkgmgr.actions.release.update_pkgbuild_version") as mock_update_pkgbuild, \
             patch("pkgmgr.actions.release.update_spec_version") as mock_update_spec, \
             patch("pkgmgr.actions.release.update_debian_changelog") as mock_update_debian_changelog, \
+            patch("pkgmgr.actions.release.update_spec_changelog") as mock_update_spec_changelog, \
             patch("pkgmgr.actions.release.run_git_command") as mock_run_git_command, \
             patch("pkgmgr.actions.release.sync_branch_with_remote") as mock_sync_branch, \
             patch("pkgmgr.actions.release.update_latest_tag") as mock_update_latest_tag:
@@ -48,7 +49,7 @@ class TestReleaseOrchestration(unittest.TestCase):
             self.assertEqual(args[1], "1.2.4")
             self.assertEqual(kwargs.get("preview"), False)
 
-            # changelog update
+            # changelog update (Projekt)
             mock_update_changelog.assert_called_once()
             args, kwargs = mock_update_changelog.call_args
             self.assertEqual(args[0], "CHANGELOG.md")
@@ -72,6 +73,13 @@ class TestReleaseOrchestration(unittest.TestCase):
                 False,
             )
 
+            # Fedora / RPM %changelog helper
+            mock_update_spec_changelog.assert_called_once()
+            self.assertEqual(
+                mock_update_spec_changelog.call_args[1].get("preview"),
+                False,
+            )
+
             # Git operations
             mock_get_current_branch.assert_called_once()
             self.assertEqual(mock_get_current_branch.return_value, "develop")
@@ -96,6 +104,7 @@ class TestReleaseOrchestration(unittest.TestCase):
             patch("pkgmgr.actions.release.update_pkgbuild_version") as mock_update_pkgbuild, \
             patch("pkgmgr.actions.release.update_spec_version") as mock_update_spec, \
             patch("pkgmgr.actions.release.update_debian_changelog") as mock_update_debian_changelog, \
+            patch("pkgmgr.actions.release.update_spec_changelog") as mock_update_spec_changelog, \
             patch("pkgmgr.actions.release.run_git_command") as mock_run_git_command, \
             patch("pkgmgr.actions.release.sync_branch_with_remote") as mock_sync_branch, \
             patch("pkgmgr.actions.release.update_latest_tag") as mock_update_latest_tag:
@@ -129,6 +138,10 @@ class TestReleaseOrchestration(unittest.TestCase):
             mock_update_debian_changelog.assert_called_once()
             self.assertTrue(mock_update_debian_changelog.call_args[1].get("preview"))
 
+            # Fedora / RPM spec changelog helper in preview mode
+            mock_update_spec_changelog.assert_called_once()
+            self.assertTrue(mock_update_spec_changelog.call_args[1].get("preview"))
+
             # In preview mode no real git commands must be executed
             mock_run_git_command.assert_not_called()