feat(harmony): stream screens over HDC without a companion app

Replace per-frame file capture with the unchanged official Hypium agent, bounded JPEG decoding, independent control RPC and scoped session cleanup. Remove the HAP build and account-signing experiment. All 85 automated checks pass; moving-screen performance and integrated phone input remain unverified because the USB device went offline. Keep published 0.3.2 artifacts unchanged.

tools/harmony-ui.test.mjs

@@ -59,6 +59,7 @@ async function app(t) {
     screenControl: false,
     screenFrameWait: null,
     screenFrameError: null,
+    screenUnchanged: false,
     openedUrls: [],
     selectedDirectory: "/fixture/folder",
     configureError: null,
@@ -105,11 +106,23 @@ async function app(t) {
       handler("hdc.screenFrame", async () => {
         if (model.screenFrameWait) await model.screenFrameWait;
         if (model.screenFrameError) throw model.screenFrameError;
+        if (model.screenUnchanged && model.screenSequence)
+          return {
+            unchanged: true,
+            width: 1200,
+            height: 2400,
+            sequence: model.screenSequence,
+            geometry: model.screenGeometry,
+            control: model.screenControl,
+            receivedFps: 0,
+            mbps: 0,
+          };
         return {
           dataUrl: "data:image/jpeg;base64,/9j/2Q==",
           width: 1200,
           height: 2400,
-          captureMs: 300,
+          receivedFps: 27,
+          mbps: 3.2,
           sequence: ++model.screenSequence,
           geometry: model.screenGeometry,
           control: model.screenControl,
@@ -473,7 +486,7 @@ test("device disconnect clears app details and prevents stale target operations"
   assert.equal($("app-launch").disabled, true);
 });
 
-test("screen viewing starts read-only, keeps refreshing and reports measured capture time", async (t) => {
+test("screen viewing starts read-only, keeps refreshing and reports stream throughput", async (t) => {
   const { $, click, tick, model } = await app(t);
   model.hdcAvailable = true;
   await click("tab-management");
@@ -482,7 +495,10 @@ test("screen viewing starts read-only, keeps refreshing and reports measured cap
   await tick();
   assert.equal($("screen-image").hidden, false);
   assert.match($("screen-status").textContent, /仅观看/);
-  assert.match($("screen-stats").textContent, /1200 × 2400.*300 ms/);
+  assert.match(
+    $("screen-stats").textContent,
+    /1200 × 2400.*接收 27 帧\/秒.*3.2 Mbps/,
+  );
   assert.equal($("screen-control").checked, false);
   assert.equal($("app-install").disabled, true);
   const before = model.screenSequence;
@@ -516,6 +532,52 @@ test("screen text and navigation require enabled control and use the displayed s
   assert.equal($("app-install").disabled, false);
 });
 
+test("an unchanged live screen preserves its image and does not count repeated frames", async (t) => {
+  const { $, click, tick, model } = await app(t);
+  model.hdcAvailable = true;
+  await click("tab-management");
+  await click("screen-start");
+  await tick();
+  await click("screen-control");
+  const source = $("screen-image").src;
+  const sequence = model.screenSequence;
+  model.screenUnchanged = true;
+  await tick();
+  await tick();
+  assert.equal($("screen-image").src, source);
+  assert.equal($("screen-image").hidden, false);
+  assert.equal(model.screenSequence, sequence);
+  assert.equal($("screen-control").checked, true);
+  assert.match($("screen-stats").textContent, /接收 0 帧\/秒/);
+  assert.ok(!model.calls.includes("hdc.screenStop"));
+});
+
+test("control does not wait behind a pending video frame", async (t) => {
+  const { $, click, tick, model } = await app(t);
+  model.hdcAvailable = true;
+  await click("tab-management");
+  await click("screen-start");
+  await tick();
+  await click("screen-control");
+  let release;
+  model.screenFrameWait = new Promise((resolve) => {
+    release = resolve;
+  });
+  await tick();
+  $("screen-inputs").querySelector('[data-screen-key="home"]').click();
+  await settle();
+  assert.ok(
+    model.parameters.some(
+      ([name, params]) =>
+        name === "hdc.screenInput" && params.input.key === "home",
+    ),
+  );
+  release();
+  model.screenFrameWait = null;
+  await settle();
+  await click("screen-stop");
+});
+
 test("stopping during a pending frame discards that response and permits a fresh screen session", async (t) => {
   const { $, click, tick, model } = await app(t);
   model.hdcAvailable = true;