feat: 支持手动切换采集帧率

在 Android、Web 及 Flutter 控制端新增帧率选择 UI，被控端按屏幕刷新率生成支持的帧率档位并上报，允许在保持分辨率不变的情况下仅切换帧率。

另附带更新信号服务器的数据库配置。

WebRTCController/app/src/main/java/com/ttstd/controller/MainActivity.java

@@ -69,6 +69,13 @@ public class MainActivity extends AppCompatActivity {
     private TextView tvStatusControl;
     private TextView tvStats;
     private Spinner spinnerResolution;
+    private Spinner spinnerFps;
+    /** 帧率下拉框当前档位（以被控端上报的 supported_fps 为准）。 */
+    private final List<Integer> fpsOptions = new ArrayList<>();
+    /** 被控端最近上报的实际采集分辨率/帧率（仅切帧率时保持分辨率不变）。 */
+    private int lastReportedWidth = 0;
+    private int lastReportedHeight = 0;
+    private int lastKnownFps = 0;
     private Button btnDisconnectControl;
 
     // 屏幕串流"自编码"模式相关 UI 与解码器
@@ -131,6 +138,7 @@ public class MainActivity extends AppCompatActivity {
         tvStatusControl = findViewById(R.id.tv_status_control);
         tvStats = findViewById(R.id.tv_stats);
         spinnerResolution = findViewById(R.id.spinner_resolution);
+        spinnerFps = findViewById(R.id.spinner_fps);
         btnDisconnectControl = findViewById(R.id.btn_disconnect_control);
 
         // 默认服务器地址
@@ -192,6 +200,7 @@ public class MainActivity extends AppCompatActivity {
         });
 
         setupResolutionSpinner();
+        setupFpsSpinner();
         updateUI(false);
 
         setupSelfCodecUi();
@@ -414,6 +423,13 @@ public class MainActivity extends AppCompatActivity {
         webRtcClient.setSelfCodecDecoder(selfCodecDecoder);
         webRtcClient.setRecorder(videoRecorder);
         webRtcClient.setStreamModeReportListener(mode -> runOnUiThread(() -> syncStreamModeUi(mode)));
+        // 被控端上报当前分辨率/帧率与支持的帧率档位 -> 同步帧率下拉框
+        webRtcClient.setResolutionReportListener((w, h, fps, supportedFps) -> runOnUiThread(() -> {
+            if (w > 0) lastReportedWidth = w;
+            if (h > 0) lastReportedHeight = h;
+            if (fps > 0) lastKnownFps = fps;
+            applyFpsOptions(supportedFps, fps);
+        }));
         webRtcClient.setConnectionListener(new WebRtcClient.ConnectionListener() {
             @Override
             public void onConnectionEstablished() {
@@ -689,6 +705,61 @@ public class MainActivity extends AppCompatActivity {
         });
     }
 
+    /** 构建帧率下拉框；档位以被控端上报（REPORT_RESOLUTION.supported_fps）为准，未上报前使用常用档位。 */
+    private void setupFpsSpinner() {
+        List<Integer> defaults = new ArrayList<>();
+        defaults.add(15);
+        defaults.add(24);
+        defaults.add(30);
+        defaults.add(60);
+        applyFpsOptions(defaults, 0);
+
+        spinnerFps.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
+            @Override
+            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
+                if (position < 0 || position >= fpsOptions.size()) return;
+                int fps = fpsOptions.get(position);
+                // 与被控端当前帧率一致时不重复发送（含上报同步 setSelection 触发的回调）
+                if (fps <= 0 || fps == lastKnownFps || webRtcClient == null) return;
+                // 仅切换帧率：分辨率沿用被控端最近上报的实际采集尺寸
+                webRtcClient.requestResolutionChange(lastReportedWidth, lastReportedHeight, fps);
+            }
+
+            @Override
+            public void onNothingSelected(AdapterView<?> parent) {
+            }
+        });
+    }
+
+    /** 更新帧率档位并把选中项同步为最接近 currentFps 的档位。 */
+    private void applyFpsOptions(List<Integer> options, int currentFps) {
+        if (spinnerFps == null) return;
+        if (options != null && !options.isEmpty() && !options.equals(fpsOptions)) {
+            fpsOptions.clear();
+            fpsOptions.addAll(options);
+            List<String> labels = new ArrayList<>();
+            for (int f : fpsOptions) labels.add(f + "fps");
+            ArrayAdapter<String> adapter = new ArrayAdapter<>(
+                    this, android.R.layout.simple_spinner_item, labels);
+            adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
+            spinnerFps.setAdapter(adapter);
+        }
+        if (currentFps > 0 && !fpsOptions.isEmpty()) {
+            int idx = 0;
+            int best = Integer.MAX_VALUE;
+            for (int i = 0; i < fpsOptions.size(); i++) {
+                int diff = Math.abs(fpsOptions.get(i) - currentFps);
+                if (diff < best) {
+                    best = diff;
+                    idx = i;
+                }
+            }
+            if (spinnerFps.getSelectedItemPosition() != idx) {
+                spinnerFps.setSelection(idx);
+            }
+        }
+    }
+
     private void updateUI(boolean connected) {
         setupPanel.setVisibility(connected ? View.GONE : View.VISIBLE);
         controlPanel.setVisibility(connected ? View.VISIBLE : View.GONE);
@@ -697,6 +768,9 @@ public class MainActivity extends AppCompatActivity {
         if (spinnerResolution != null) {
             spinnerResolution.setEnabled(connected);
         }
+        if (spinnerFps != null) {
+            spinnerFps.setEnabled(connected);
+        }
         if (tvStatusControl != null) {
             tvStatusControl.setText(connected ? "远程控制中" : "未连接");
         }

WebRTCController/app/src/main/java/com/ttstd/controller/webrtc/WebRtcClient.java

@@ -71,6 +71,17 @@ public class WebRtcClient {
         void onStreamModeReported(int mode);
     }
 
+    /** 被控端上报当前采集分辨率/帧率与支持的帧率档位（REPORT_RESOLUTION）。 */
+    public interface ResolutionReportListener {
+        void onResolutionReported(int width, int height, int fps, List<Integer> supportedFps);
+    }
+
+    private ResolutionReportListener resolutionReportListener;
+
+    public void setResolutionReportListener(ResolutionReportListener l) {
+        this.resolutionReportListener = l;
+    }
+
     private ConnectionListener connectionListener;
 
     public WebRtcClient(Context context, WebSocketClient wsClient, String deviceId) {
@@ -371,10 +382,16 @@ public class WebRtcClient {
                             streamModeReportListener.onStreamModeReported(msg.getStreamMode());
                         }
                     } else if (msg.getAction() == Action.REPORT_RESOLUTION) {
-                        Log.i(TAG, "Received resolution report: " + msg.getWidth() + "x" + msg.getHeight());
+                        Log.i(TAG, "Received resolution report: " + msg.getWidth() + "x" + msg.getHeight()
+                                + " @ " + msg.getFps() + "fps, supportedFps=" + msg.getSupportedFpsList());
                         if (selfCodecDecoder != null) {
                             selfCodecDecoder.updateResolution(msg.getWidth(), msg.getHeight());
                         }
+                        if (resolutionReportListener != null) {
+                            resolutionReportListener.onResolutionReported(
+                                    msg.getWidth(), msg.getHeight(), msg.getFps(),
+                                    new ArrayList<>(msg.getSupportedFpsList()));
+                        }
                     }
                 } catch (Exception ignored) {
                 }

WebRTCController/app/src/main/proto/control_message.proto

@@ -51,4 +51,7 @@ message ControlMessage {
   int32 height = 13;
   int32 fps = 14;
   int32 stream_mode = 15; // 串流模式：0=WebRTC 内置媒体流，1=自编码(MediaCodec 硬编 + DataChannel 透传)
+
+  // 被控端支持的帧率档位列表（REPORT_RESOLUTION 上报，按屏幕刷新率筛选，升序）。
+  repeated int32 supported_fps = 16;
 }

WebRTCController/app/src/main/res/layout/activity_main.xml

@@ -152,6 +152,13 @@
                 android:layout_marginTop="4dp"
                 android:backgroundTint="#80FFFFFF" />
 
+            <Spinner
+                android:id="@+id/spinner_fps"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="4dp"
+                android:backgroundTint="#80FFFFFF" />
+
             <Button
                 android:id="@+id/btn_disconnect_control"
                 android:layout_width="wrap_content"