Merge Phase 6 and reconcile offline completion, response capture and contract tests

frontend/asset-sync-core.test.js

@@ -96,3 +96,9 @@ test('metadata probes release response streams while stored asset bodies remain
  assert.equal((await core.status(m,c)).offlineReady,true);assert.ok(probes.length>0);assert.ok(probes.every(r=>r.bodyUsed));
  assert.equal(await(await match('/a.js?v=a')).text(),'a');assert.equal(await(await match('/index.html?v=b')).text(),'b');
 });
+
+test('stale app core requires every feature contract to match the new shell',()=>{
+ const old={files:{'/app.js':{h:'old'}},groups:{core:{contract:1,files:['/app.js']},extra:{contract:1,files:[]}}};
+ const next=structuredClone(old);next.files['/app.js'].h='new';next.groups.extra.contract=2;
+ assert.equal(core.fallback(next,old,'/app.js'),null);next.groups.extra.contract=1;assert.equal(core.fallback(next,old,'/app.js'),'/app.js?v=old');
+});