Complete accessibility identifier coverage across all 152 project files

Exhaustive file-by-file audit of every Swift file in the project (iOS app,
Watch app, Widget extension). Every interactive UI element — buttons, toggles,
pickers, links, menus, tap gestures, text editors, color pickers, photo
pickers — now has an accessibilityIdentifier for XCUITest automation.

46 files changed across Shared/, Onboarding/, Watch App/, and Widget targets.
Added ~100 new ID definitions covering settings debug controls, export/photo
views, sharing templates, customization subviews, onboarding flows, tip
modals, widget voting buttons, and watch mood buttons.

Shared/ReflectApp.swift

@@ -73,6 +73,7 @@ struct ReflectApp: App {
                 .alert("Data Storage Unavailable",
                        isPresented: $showStorageFallbackAlert) {
                     Button("OK", role: .cancel) { }
+                        .accessibilityIdentifier(AccessibilityID.AppAlert.storageUnavailableOK)
                 } message: {
                     Text("Your mood data cannot be saved permanently. Please restart the app. If the problem persists, reinstall the app.")
                 }