Clarify and strengthen state invariant tests

test/server/state-contract.test.js

@@ -90,7 +90,7 @@ test('state v1 normalizes legacy storage and validates the canonical snapshot',
   );
 });
 
-test('GET and domain mutations return one state shape with monotonic revisions', async (t) => {
+test('data invariant: API mutations return one snapshot, increase revision and roll back subscription failures', async (t) => {
   const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'harbor-state-contract-'));
   const binDir = path.join(dir, 'bin');
   const config = {

test/server/state-store.test.js

@@ -17,7 +17,7 @@ const fixture = (t) => {
   return path.join(directory, 'state.json');
 };
 
-test('a failure before rename preserves the last successful file', (t) => {
+test('data invariant: failure before rename preserves the last successful file', (t) => {
   const filePath = fixture(t);
   atomicWriteJson(filePath, { revision: 1 });
 
@@ -79,7 +79,7 @@ test('ambiguous legacy selectedTag explicitly requires a new choice', (t) => {
   assert.equal(migrated.servers.length, 2);
 });
 
-test('corrupt JSON is preserved and replaced with an explicit recovery state', (t) => {
+test('data invariant: corrupt JSON preserves original bytes and returns explicit recovery state', (t) => {
   const filePath = fixture(t);
   fs.writeFileSync(filePath, '{broken');