feat(version): derive display versions from release tags

Resolve user-facing versions from SemVer release tags and available local
history while retaining raw package metadata for API identity. Stamp Desktop
provenance at build time, and expose generic version details for every
Desktop install method.

tests/scripts/test_release_tags.py

@@ -0,0 +1,31 @@
+"""Release-tag policy: new releases use semver, old CalVer tags remain readable."""
+
+import importlib.util
+from pathlib import Path
+
+
+_RELEASE_PATH = Path(__file__).resolve().parents[2] / "scripts" / "release.py"
+_SPEC = importlib.util.spec_from_file_location("hermes_release", _RELEASE_PATH)
+assert _SPEC and _SPEC.loader
+release = importlib.util.module_from_spec(_SPEC)
+_SPEC.loader.exec_module(release)
+
+
+def test_release_tag_uses_the_semver_version():
+    assert release.release_tag_for_version("0.20.0") == "v0.20.0"
+
+
+def test_last_tag_prefers_semver_over_newer_looking_legacy_calver(monkeypatch):
+    monkeypatch.setattr(
+        release,
+        "git",
+        lambda *_args: "v2026.7.20\nv0.20.0\nv0.19.0",
+    )
+
+    assert release.get_last_tag() == "v0.20.0"
+
+
+def test_last_tag_falls_back_to_legacy_calver_history(monkeypatch):
+    monkeypatch.setattr(release, "git", lambda *_args: "v2026.7.20\nv2026.7.7")
+
+    assert release.get_last_tag() == "v2026.7.20"