Fix shared Go Live camera capture race

Author: KSemenenko

AGENTS.md

@@ -506,6 +506,7 @@ Ask first:
 - hardcoded fallback reader/test fixtures such as inline `Ready` chunks, fake word models, or synthetic UI state embedded directly in tests when the same behavior can be exercised through shared script fixtures, builders, or production-owned constants
 - agent-started local servers taking shared user ports or using ports outside the reserved `5050-5070` agent range
 - brittle selectors without dedicated test attributes
+- any assumption that local Playwright or MCP browser automation must use Chrome; prefer `msedge` when a browser flag is needed because the user's local workflow is Edge-first
 - progress updates that imply a fix is done before there is concrete implementation and verification evidence; keep status factual and let the user verify final behavior personally
 - slow repo-wide serialized test runs as the default for small UI fixes when targeted component/browser suites already cover the changed slice; prefer the fastest relevant proof first and only escalate to the slow full solution path when the user explicitly asks for it
 - long-running local import or conversion flows that leave the shell looking frozen; file import must expose a visible in-app busy/progress state and a clear completion or failure transition

src/PrompterOne.Shared/GoLive/Pages/GoLivePage.CameraLifecycle.cs

@@ -1,5 +1,3 @@
-using Microsoft.JSInterop;
-
 namespace PrompterOne.Shared.Pages;
 
 public partial class GoLivePage

src/PrompterOne.Shared/GoLive/Pages/GoLivePage.Notifications.cs

@@ -1,4 +1,3 @@
-using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Components.Routing;
 using PrompterOne.Shared.Contracts;
 

src/PrompterOne.Shared/wwwroot/media/browser-media.js

@@ -6,6 +6,7 @@
     const defaultDeviceId = "default";
     const microphoneMonitorLevelMultiplier = 2800;
     const monitorMap = new Map();
+    const pendingCameraCaptureMap = new Map();
     const remoteCaptureMap = new Map();
     const remoteStreamMap = new Map();
     const appleVendorFragment = "Apple";
@@ -396,17 +397,43 @@
         }
     }
 
+    function createCameraCapture(deviceId) {
+        const liveKitClient = getLiveKitClient();
+        return liveKitClient.createLocalVideoTrack(getTrackCaptureOptions(deviceId)).then(track => ({
+            refCount: 0,
+            track
+        }));
+    }
+
+    async function getOrCreateCameraCapture(captureKey, deviceId) {
+        const existingCapture = cameraCaptureMap.get(captureKey);
+        if (existingCapture) {
+            return existingCapture;
+        }
+
+        let pendingCapture = pendingCameraCaptureMap.get(captureKey);
+        if (!pendingCapture) {
+            pendingCapture = createCameraCapture(deviceId);
+            pendingCameraCaptureMap.set(captureKey, pendingCapture);
+        }
+
+        try {
+            const resolvedCapture = await pendingCapture;
+            if (!cameraCaptureMap.has(captureKey)) {
+                cameraCaptureMap.set(captureKey, resolvedCapture);
+            }
+
+            return cameraCaptureMap.get(captureKey);
+        } finally {
+            if (pendingCameraCaptureMap.get(captureKey) === pendingCapture) {
+                pendingCameraCaptureMap.delete(captureKey);
+            }
+        }
+    }
+
     async function acquireCameraCapture(deviceId) {
         const captureKey = getCaptureKey(deviceId);
-        let capture = cameraCaptureMap.get(captureKey);
-        if (!capture) {
-            const liveKitClient = getLiveKitClient();
-            capture = {
-                refCount: 0,
-                track: await liveKitClient.createLocalVideoTrack(getTrackCaptureOptions(deviceId))
-            };
-            cameraCaptureMap.set(captureKey, capture);
-        }
+        const capture = await getOrCreateCameraCapture(captureKey, deviceId);
 
         capture.refCount += 1;
         const stream = new MediaStream([capture.track.mediaStreamTrack]);

tests/PrompterOne.Web.UITests.Studio/GoLive/GoLiveMediaCleanupLifecycleTests.cs

@@ -210,6 +210,10 @@ await page.WaitForFunctionAsync(
 
             var activeVideoTrackCount = await page.EvaluateAsync<int>(BrowserTestConstants.Media.GetActiveVideoTrackCountScript);
             await Assert.That(activeVideoTrackCount).IsGreaterThan(0);
+            var activePrimaryCameraTrackCount = await page.EvaluateAsync<int>(
+                BrowserTestConstants.Media.GetActiveVideoTrackCountForDeviceScript,
+                BrowserTestConstants.Media.PrimaryCameraId);
+            await Assert.That(activePrimaryCameraTrackCount).IsEqualTo(BrowserTestConstants.Media.ExpectedVideoTrackCount);
 
             await page.GetByTestId(UiTestIds.GoLive.Back).ClickAsync();
             await page.WaitForURLAsync(BrowserTestConstants.Routes.Pattern(BrowserTestConstants.Routes.Library));

tests/PrompterOne.Web.UITests/Media/BrowserTestConstants.Media.cs

@@ -58,6 +58,8 @@ public static class Media
             $$"""testId => { const element = document.querySelector(`[data-test="${testId}"]`); return window["{{HarnessGlobal}}"].getElementState(element?.id ?? ""); }""";
         public static string GetActiveVideoTrackCountScript =>
             $$"""() => window["{{HarnessGlobal}}"].getActiveTrackCount({ kind: "video" })""";
+        public static string GetActiveVideoTrackCountForDeviceScript =>
+            $$"""deviceId => window["{{HarnessGlobal}}"].getActiveTrackCount({ kind: "video", deviceId })""";
         public static string GetActiveVideoTracksScript =>
             $$"""() => window["{{HarnessGlobal}}"].getActiveTracks({ kind: "video" })""";
         public static string HasNoActiveVideoTracksScript =>