chore: clear dead test and allowlist leftovers of dropped runtimes

tests/host-integration.test.cjs

@@ -2875,12 +2875,12 @@ describe('#2627 dispatch-isolation CLI route', () => {
   test('raw output is the bare negotiated value for each isolation model', () => {
     assert.equal(query('claude').trim(), 'harness-worktree');
     assert.equal(query('codex').trim(), 'orchestrator-worktree');
-    assert.equal(query('pi').trim(), 'none');
+    assert.equal(query('zcode').trim(), 'none');
   });
 
   test('an undocumented isolation declaration degrades to none (fail-closed)', () => {
-    // cline declares isolation:"undocumented" — the corpus-wide sentinel.
-    assert.equal(query('cline').trim(), 'none');
+    // antigravity declares isolation:"undocumented" — the corpus-wide sentinel.
+    assert.equal(query('antigravity').trim(), 'none');
   });
 
   test('an unknown runtime degrades to none rather than erroring', () => {