test(perf): add the serial-depth fields to the J3 IPC capture fixture (#1797)

#1773 added `ambiguousTimelineCompletions` and `timeline` to
`JourneyMainIpcCaptureState`, while #1774 merged the J3 playback record
spec with a fixture of the old shape, so the spec no longer type-checks
(TS2739). The harness runs it through tsx without type checking, so CI
stayed green.

The timeline holds one start per counted call, matching `callsByMethod`
and `callsBeforeSentinel`, so the fixture stays a capture a real run
could produce.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

apps/electron-backend-e2e/src/performance/playback-journey-record.spec.ts

@@ -100,6 +100,7 @@ function measurement(
         },
     };
     const ipc: JourneyMainIpcCaptureState = {
+        ambiguousTimelineCompletions: 0,
         callsAfterSentinel: 3,
         callsBeforeStart: 6,
         callsBeforeSentinel: 4,
@@ -116,6 +117,16 @@ function measurement(
         senderIds: [1],
         sentinel: { occurrences: 1, receivedEpochMs: 10_351 },
         start: { occurrences: 1, receivedEpochMs: 10_001 },
+        timeline: [
+            { method: 'setUserAgent', phase: 'start' },
+            { method: 'setUserAgent', phase: 'end' },
+            { method: 'xtreamRequest', phase: 'start' },
+            { method: 'getEpgMapping', phase: 'start' },
+            { method: 'getEpgMapping', phase: 'end' },
+            { method: 'updateRemoteControlStatus', phase: 'start' },
+            { method: 'updateRemoteControlStatus', phase: 'end' },
+            { method: 'xtreamRequest', phase: 'end' },
+        ],
         unmatchedCompletions: 0,
     };
     return {