fix: improve recovery and auto-start flows

src/LiveRecorder.Infrastructure/Services/FfmpegService.Utils.cs

@@ -80,7 +80,9 @@ public sealed partial class FfmpegService
         var stderrLines = new Queue<string>();
         var progressSync = new object();
         double? processedSeconds = null;
-        var lastReportedWholePercent = -1;
+        double? lastReportedProgressPercent = null;
+        string? lastReportedStage = null;
+        string? lastReportedDetail = null;
         var attemptStartedAt = DateTimeOffset.UtcNow;
         var activeStage = "Finalizing MP4";
         var maxDuration = TimeSpan.FromMinutes(Math.Clamp(mp4FinalizeTimeoutMinutes, 1, 1440));
@@ -114,19 +116,28 @@ public sealed partial class FfmpegService
                     detail = $"Processed {processedSeconds.Value:F1}s";
                 }
 
-                var wholePercent = progressPercent.HasValue ? (int)Math.Floor(progressPercent.Value) : -1;
-                if (stageOverride is null && wholePercent == lastReportedWholePercent)
+                var effectiveStage = stageOverride ?? activeStage;
+                var normalizedProgressPercent = progressPercent.HasValue
+                    ? Math.Round(progressPercent.Value, 1, MidpointRounding.AwayFromZero)
+                    : (double?)null;
+                var effectiveDetail = detail ?? $"Optimizing MP4 index for {Path.GetFileName(targetPath)}";
+
+                if (string.Equals(effectiveStage, lastReportedStage, StringComparison.Ordinal) &&
+                    string.Equals(effectiveDetail, lastReportedDetail, StringComparison.Ordinal) &&
+                    Nullable.Equals(normalizedProgressPercent, lastReportedProgressPercent))
                 {
                     return;
                 }
 
-                lastReportedWholePercent = wholePercent;
+                lastReportedStage = effectiveStage;
+                lastReportedDetail = effectiveDetail;
+                lastReportedProgressPercent = normalizedProgressPercent;
                 SetPostProcessState(
                     recordSessionId,
                     recordTaskId,
-                    stageOverride ?? activeStage,
-                    progressPercent,
-                    detail ?? $"Optimizing MP4 index for {Path.GetFileName(targetPath)}");
+                    effectiveStage,
+                    normalizedProgressPercent,
+                    effectiveDetail);
             }
         }
 
@@ -159,7 +170,9 @@ public sealed partial class FfmpegService
             ClearErrorDetail();
             activeStage = stage;
             processedSeconds = null;
-            lastReportedWholePercent = -1;
+            lastReportedProgressPercent = null;
+            lastReportedStage = null;
+            lastReportedDetail = null;
             attemptStartedAt = DateTimeOffset.UtcNow;
             System.Threading.Interlocked.Exchange(ref lastActivityTicks, attemptStartedAt.UtcTicks);