feat(cast): DLNA/UPnP casting as first-class GSY capability (jUPnP 3.0.3)

Refactor the cast feature from a private HTTP loopback demo into a
kernel-native DLNA/UPnP capability shipped with gsyVideoPlayer-java.

Kernel side (gsyVideoPlayer-java/.../cast):
- CastCapability facade + CastProvider/CastSession/CastListener SPI so
  callers depend on a stable API instead of protocol details.
- CastMediaInfo carries an immutable startPositionMs so casting from a
  mid-playback position no longer restarts from 0 on the remote end.
- DLNA provider stack (dlna/JupnpDlnaProvider, JupnpDlnaSession,
  DidlLite) implemented on top of jUPnP 3.0.3 support library:
  SetAVTransportURI -> Play -> Seek chain, 1Hz GetPositionInfo /
  GetTransportInfo polling, DIDL-Lite metadata, seek/pause/stop.
- Registered as an optional module inside GSYVideoBaseManager so it can
  be enabled/disabled without touching video_layout_standard.

App demo side:
- SampleCastControlVideo collapses to a remote-control overlay while
  casting, releases the local surface, and resumes at the last remote
  position on disconnect. Reads local position on the main thread
  before releaseAllVideos and forwards it via CastMediaInfo.
- CastDemoActivity + activity_cast_demo layout expose the DLNA device
  picker, connect/disconnect flow, and the loopback receiver toggle.
- Loopback dev receiver (DevReceiverService, LoopbackDeviceFactory,
  LoopbackAvTransportService, LoopbackRenderingControlService) runs in
  a dedicated :dlna process and advertises a fake TV so the whole SOAP
  path can be smoke-tested on one phone.
- CastReceiverFloatingWindow + CastReceiverPlayer + CastReceiverManager
  render the incoming stream in a system-alert floating window and
  expose read-only position/duration/state snapshots that the loopback
  AVTransport service feeds back to the sender.
- DevReceiverService broadcasts READY/STOPPED/ERROR across the :dlna
  boundary via setPackage-scoped intents (with RECEIVER_NOT_EXPORTED on
  API 33+), because static listener fields are invisible across
  processes; CastDemoActivity registers a BroadcastReceiver in
  onStart/onStop to keep the toggle label in sync.

Cleanup:
- Delete the legacy gsyVideoPlayer-cast module, the standalone
  gsy-cast-receiver JavaFX project, and the private GSY-Cast v1 HTTP
  protocol together with their unit tests; the DLNA capability
  supersedes all of them.
- Update settings.gradle, gradle/dependencies.gradle, and
  gsyVideoPlayer-java/build.gradle to wire jUPnP 3.0.3 and drop the
  removed modules.
- Refresh doc/CAST_FEATURE_PLAN.md and doc/CAST_TEST_PLAYBOOK.md to
  describe the DLNA-first architecture and the loopback smoke test.

All strings live in res/values{,-zh-rCN}/strings.xml, no hardcoded
copy. AVTransport heavy lifting runs on a dedicated executor so the UI
thread only touches surface/state changes.

Author: CarGuo

.gitignore

@@ -326,6 +326,14 @@ keyid
 .idea/
 .junie/
 
+# Local cast E2E debugging scratch (M4)
+m4-*.json
+m4-shots/
+m4-receiver.log
+
+# Cast E2E scratch (uiautomator dumps, screenshots)
+.tmp/
+
 # Secrets for local act testing
 .secrets
 *.asc

README.md

@@ -30,6 +30,7 @@
  **openssl** | **Currently ex_so's arm64/x86_64  uses openssl 1.1.1w**
  **FFmpeg**  | **Currently ex_so's arm64/x86_64 uses FFmpeg 4.3**
  **FFmpeg**  | **Currently ex_so's arm64/x86_64  supports G711a(pcm_alaw)**
+ **Cast**      | **First-class DLNA/UPnP casting built on jUPnP 3.0.3; `CastCapability` / `CastProvider` / `CastSession` SPI, `SetAVTransportURI → Play → Seek` chain preserves the local position when casting mid-playback; ships with a single-device Loopback Receiver for on-device smoke tests. [Details](doc/CAST_FEATURE_PLAN.md).**
  **More**      | **No black screen when pausing front and back switching; multi-URL quality switching; Exo HLS/DASH adaptive quality; seamless switching support; keep-last-frame demo; WebVTT progress bar preview.**
  **Customization**     | **Customizable rendering layer, custom management layer, custom playback layer (control layer), custom cache layer.**
 
@@ -488,6 +489,14 @@ Library APIs include `GSYVideoPreviewVttParser`, `GSYVideoPreviewProvider`, and
 
 ## V. Recent Versions
 
+### Unreleased / feature/cast-capability
+
+- Add first-class DLNA/UPnP cast capability inside `gsyVideoPlayer-java`: `CastCapability` / `CastProvider` / `CastSession` / `CastListener` SPI are the stable public contract, and the default `JupnpDlnaProvider` / `JupnpDlnaSession` implementation speaks DLNA `AVTransport:1` on top of jUPnP 3.0.3.
+- `CastMediaInfo` now carries an immutable `startPositionMs` field. The `SetAVTransportURI → Play → Seek` chain guarantees "casting mid-playback resumes at the same position remotely" and disconnect returns the local player to the last known remote position.
+- `SampleCastControlVideo` collapses into a remote-control overlay while casting — the local surface and audio are released, and a clean resume path restores local playback on disconnect. `CastDemoActivity` provides the DLNA device picker plus a Loopback Receiver toggle.
+- Ships an on-device Loopback Receiver (`DevReceiverService` in `:dlna` process + `LoopbackAvTransportService` + `CastReceiverFloatingWindow`) for end-to-end smoke tests without a real TV. Cross-process state is bridged with `sendBroadcast` + `setPackage` private intents.
+- All strings live in `res/values{,-zh-rCN}/strings.xml`. Android 13+ receivers use `RECEIVER_NOT_EXPORTED` and the notification/foreground-service permission model is honoured.
+
 ### v13.1.0 (2026-06-30)
 
 - Publish the `gsyvideoplayer-compose` artifact and document Maven Central / GitHub Packages coordinates.

README_CN.md

@@ -31,6 +31,7 @@
  **openssl** | **目前  ex_so 的 arm64/x86_64 使用 openssl 1.1.1w**
  **FFmpeg**  | **目前  ex_so 的 arm64/x86_64 使用 FFmpeg 4.3**
  **FFmpeg**  | **目前  ex_so 的 arm64/x86_64 支持 G711a(pcm_alaw)**
+ **投屏**      | **内核一等公民 DLNA/UPnP 投屏能力，基于 jUPnP 3.0.3；`CastCapability` / `CastProvider` / `CastSession` SPI，SetAVTransportURI → Play → Seek 支持中途投屏保留本地进度；带单机 Loopback Receiver 便于自测。[说明](doc/CAST_FEATURE_PLAN.md)。**
  **更多**      | **暂停前后台切换不黑屏；多 URL 清晰度切换；Exo HLS/DASH 自适应清晰度；无缝切换支持；完成后保留最后一帧 Demo；进度条 WebVTT 小窗口预览。**
  **自定义**     | **可自定义渲染层、自定义管理层、自定义播放层（控制层）、自定义缓存层。**
 
@@ -490,6 +491,14 @@ WEBVTT
 
 ## 五、近期版本
 
+### 未发布 / feature/cast-capability
+
+- 新增 DLNA/UPnP 投屏能力，作为 `gsyVideoPlayer-java` 内核一等公民：`CastCapability` / `CastProvider` / `CastSession` / `CastListener` SPI 接口稳定对外，默认实现 `JupnpDlnaProvider` / `JupnpDlnaSession` 基于 jUPnP 3.0.3 走 DLNA `AVTransport:1` 标准协议。
+- 投屏 `CastMediaInfo` 支持不可变 `startPositionMs` 字段，`SetAVTransportURI → Play → Seek` 链路保证"本地播到 40% → 投屏后从 40% 继续"，断开后本地在最近远端位置继续。
+- `SampleCastControlVideo` 演示塌陷成远端遥控 overlay，投屏时释放本地 surface / audio，断开后无缝恢复本地播放；`CastDemoActivity` 提供 DLNA 设备选择 + Loopback 接收器开关。
+- 内置 `DevReceiverService` (`:dlna` 独立进程) + `LoopbackAvTransportService` + `CastReceiverFloatingWindow` 组成单机 Loopback Receiver，便于在没有真电视时端到端自测；跨进程状态用 `sendBroadcast` + `setPackage` 私有广播回填。
+- 文案全部走 `res/values{,-zh-rCN}/strings.xml`，Android 13+ 已适配 `RECEIVER_NOT_EXPORTED` / `POST_NOTIFICATIONS` 权限模型。
+
 ### v13.1.0 (2026-06-30)
 
 - 发布 `gsyvideoplayer-compose` artifact，并补齐 Maven Central / GitHub Packages 依赖坐标说明。

app/build.gradle

@@ -11,6 +11,11 @@ android {
         versionCode 21
         versionName PROJ_VERSION
 
+        // M7-a-5：jUPnP 3.x 依赖 Jetty 9.4，Jetty 9.4 底层用了 MethodHandle.invoke，
+        // 这是 VM level 能力，D8 core-library-desugaring 无法降级，官方 dex 起步就是 API 26。
+        // 因此 :app（也只有 :app 需要 DLNA 能力）单独把 minSdk 提到 26。内核 AAR 依旧 23。
+        minSdk 26
+
         multiDexEnabled true
 
         ndk {
@@ -118,10 +123,16 @@ dependencies {
     implementation dataDependencies.okhttpUtil
     implementation dataDependencies.okhttp
 
+    // M7-a-4: NanoHTTPD for the in-app Loopback DevReceiver's HTTP control server.
+    implementation dataDependencies.nanohttpd
+
     implementation dataDependencies.permissionsDispatcher
     annotationProcessor dataDependencies.permissionsDispatcherProcessor
 
     debugImplementation dataDependencies.leakcanary
 
     implementation 'androidx.activity:activity:1.10.1'
+
+    //M2d 投屏 demo 纯 JVM 单元测试（SampleCastControlVideo 的静态工具方法）
+    testImplementation testDependencies.junit
 }

app/src/main/AndroidManifest.xml

@@ -10,6 +10,24 @@
     <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
     <uses-permission android:name="android.permission.WRITE_SETTINGS"
         tools:ignore="ProtectedPermissions" />
+    <!-- M7-a-3 mDNS discovery: WifiManager.MulticastLock lets us receive 224.0.0.251:5353
+         packets on vendor ROMs (Xiaomi/Huawei/OPPO) that filter multicast in power save. -->
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+    <uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
+    <!-- M7-a-5 jUPnP：MulticastSocket 长时间收 SSDP，需要 WAKE_LOCK 避免 doze 掉线；
+         Android 12+ (API 33+) SSDP 属于 nearby wifi 用途，需要 NEARBY_WIFI_DEVICES 权限。 -->
+    <uses-permission android:name="android.permission.WAKE_LOCK" />
+    <uses-permission android:name="android.permission.NEARBY_WIFI_DEVICES"
+        android:usesPermissionFlags="neverForLocation"
+        tools:targetApi="33" />
+
+    <!-- M7-a-4 in-app Loopback DevReceiver: foreground service (media playback) hosts the
+         mDNS advertiser + NanoHTTPD control server; notification requires POST_NOTIFICATIONS
+         on Android 13+. FOREGROUND_SERVICE_MEDIA_PLAYBACK is only enforced on targetSdk 34+
+         but we declare it now for forward compatibility. -->
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
 
     <application
         android:name=".GSYApplication"
@@ -253,6 +271,33 @@
             android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"
             android:screenOrientation="portrait"
             android:theme="@style/Theme.AppCompat.Transitions" />
+        <activity
+            android:name=".CastDemoActivity"
+            android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"
+            android:exported="true"
+            android:screenOrientation="portrait"
+            android:theme="@style/Theme.AppCompat.Transitions" />
+
+        <!-- Loopback DevReceiver 现在渲染在应用内悬浮小窗（CastReceiverFloatingWindow）
+             + 独立的 CastReceiverManager IJK 实例，不再拉起独立 Activity。原先的
+             .cast.DevReceiverPlayerActivity 已随架构重构一并删除。 -->
+
+        <!-- M7-a-5 主进程 DLNA 发现栈：JupnpDlnaProvider 通过 bindService 挂到这里，
+             用 AndroidUpnpServiceConfiguration + AndroidRouter 承担 SSDP 客户端职责。
+             与 :dlna 进程内的 UpnpServiceImpl（receiver）走不同进程/不同 socket。 -->
+        <service
+            android:name="org.jupnp.android.AndroidUpnpServiceImpl"
+            android:exported="false" />
+
+        <!-- M7-a-5 Loopback DevReceiver：跑在独立进程 :dlna。这样主进程 sender 侧的
+             jUPnP 发现栈 + 本地 receiver 端 jUPnP 栈各占各的 UDP socket / Registry，
+             天然避免 M-SEARCH 自己看不到自己的坑。
+             foregroundServiceType=mediaPlayback 匹配 Android 14+ allowlist 要求。 -->
+        <service
+            android:name=".cast.DevReceiverService"
+            android:exported="false"
+            android:foregroundServiceType="mediaPlayback"
+            android:process=":dlna" />
         <activity
             android:name=".compose.ComposeDemoListActivity"
             android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"