fix(render): cap final mux to video duration

packages/producer/src/services/distributed/assemble.ts

@@ -323,7 +323,11 @@ export async function assemble(
         audioForMux,
         muxOutputPath,
         abortSignal,
-        { audioCodec: "aac", preserveAudioPrimingEditList },
+        {
+          audioCodec: "aac",
+          preserveAudioPrimingEditList,
+          durationSeconds: padTrimResult.targetDurationSeconds,
+        },
         { num: plan.dimensions.fpsNum, den: plan.dimensions.fpsDen },
       );
       if (!muxResult.success) {

packages/producer/src/services/render/stages/assembleStage.ts

@@ -79,6 +79,7 @@ export async function runAssembleStage(input: AssembleStageInput): Promise<Assem
       {
         audioCodec: "aac",
         preserveAudioPrimingEditList: normalizeResult.operation === "trim",
+        durationSeconds: normalizeResult.targetDurationSeconds,
       },
       job.config.fps,
     );