Add SemVer VERSION, Jenkins CI/CD, and release 0.1.1.

Ship Harbor/Hub push with latest+version tags, deploy to proxmox.devops.org.ru, and show the package version badge in Help → About.

tests/unit/test_version.py

@@ -0,0 +1,14 @@
+"""SemVer helpers."""
+
+from __future__ import annotations
+
+from app.version import get_app_version, get_app_version_label, parse_version
+
+
+def test_get_app_version_reads_version_file() -> None:
+    version = get_app_version()
+    major, minor, patch = parse_version(version)
+    assert major >= 0
+    assert minor >= 0
+    assert patch >= 0
+    assert get_app_version_label() == f"v{version}"