remove backend dependency from iOS demo reveal

mobile/ios-app/Features/Round/RoundView.swift

@@ -329,7 +329,20 @@ struct RoundView: View {
             return
         }
 
-        guard let selectedOutcomeID, let session = repository.currentSession else {
+        guard let selectedOutcomeID else {
+            actionMessage = localization.string(for: "errors.session_expired")
+            return
+        }
+
+        if isDemoMode {
+            analytics.track("selection_submitted", attributes: baseSelectionAttributes(selectedOutcomeID))
+            analytics.track("selection_accepted", attributes: baseSelectionAttributes(selectedOutcomeID))
+            analytics.track("market_locked", attributes: baseSelectionAttributes(selectedOutcomeID).merging(["lock_reason": "swipe_selection"]) { _, new in new })
+            beginRevealTransition(for: round, selectedOutcomeID: selectedOutcomeID)
+            return
+        }
+
+        guard let session = repository.currentSession else {
             actionMessage = localization.string(for: "errors.session_expired")
             return
         }
@@ -371,21 +384,7 @@ struct RoundView: View {
                 analytics.track("selection_submitted", attributes: baseSelectionAttributes(selectedOutcomeID))
                 analytics.track("selection_accepted", attributes: baseSelectionAttributes(selectedOutcomeID))
                 analytics.track("market_locked", attributes: baseSelectionAttributes(selectedOutcomeID).merging(["lock_reason": "swipe_selection"]) { _, new in new })
-
+                beginRevealTransition(for: round, selectedOutcomeID: selectedOutcomeID)
-                phase = .locked
-                playerCoordinator.play(rate: 2.0)
-
-                transitionTask?.cancel()
-                transitionTask = Task { @MainActor in
-                    try? await Task.sleep(nanoseconds: 1_100_000_000)
-                    guard !Task.isCancelled else {
-                        return
-                    }
-
-                    phase = .reveal
-                    playerCoordinator.play(url: revealMediaURL(for: round), startTimeMs: revealStartTimeMs(for: round), rate: 1.0)
-                    analytics.track("reveal_started", attributes: roundAnalyticsAttributes(round).merging(baseSelectionAttributes(selectedOutcomeID)) { _, new in new })
-                }
             } catch {
                 actionMessage = hermesUserFacingErrorMessage(localization: localization, localeCode: localization.localeCode, error: error) ?? localization.string(for: "errors.generic")
                 phase = .preview
@@ -395,6 +394,23 @@ struct RoundView: View {
         }
     }
 
+    private func beginRevealTransition(for round: HermesRound, selectedOutcomeID: String) {
+        phase = .locked
+        playerCoordinator.play(rate: 2.0)
+
+        transitionTask?.cancel()
+        transitionTask = Task { @MainActor in
+            try? await Task.sleep(nanoseconds: 1_100_000_000)
+            guard !Task.isCancelled else {
+                return
+            }
+
+            phase = .reveal
+            playerCoordinator.play(url: revealMediaURL(for: round), startTimeMs: revealStartTimeMs(for: round), rate: 1.0)
+            analytics.track("reveal_started", attributes: roundAnalyticsAttributes(round).merging(baseSelectionAttributes(selectedOutcomeID)) { _, new in new })
+        }
+    }
+
     private func showResult() {
         guard let round = repository.currentRound, let selectedOutcomeID else {
             return
@@ -431,6 +447,10 @@ struct RoundView: View {
         repository.currentSession?.deviceModel == "Demo Device" ? MockHermesData.revealMediaURL() : round.media.hlsMasterUrl
     }
 
+    private var isDemoMode: Bool {
+        repository.currentSession?.deviceModel == "Demo Device"
+    }
+
     private func revealStartTimeMs(for round: HermesRound) -> Int {
         repository.currentSession?.deviceModel == "Demo Device" ? 0 : round.media.revealStartMs
     }