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/Views/ExportView.swift

@@ -104,6 +104,7 @@ struct ExportView: View {
                     Button("Cancel") {
                         dismiss()
                     }
+                    .accessibilityIdentifier(AccessibilityID.Export.cancelButton)
                 }
             }
             .sheet(isPresented: $showShareSheet) {
@@ -113,6 +114,7 @@ struct ExportView: View {
             }
             .alert("Export Failed", isPresented: $showError) {
                 Button("OK", role: .cancel) { }
+                    .accessibilityIdentifier(AccessibilityID.Export.alertOKButton)
             } message: {
                 Text(errorMessage)
             }
@@ -230,6 +232,7 @@ struct ExportView: View {
                     )
                 }
                 .buttonStyle(.plain)
+                .accessibilityIdentifier(AccessibilityID.Export.formatButton(format.rawValue))
             }
         }
     }
@@ -260,6 +263,7 @@ struct ExportView: View {
                         .background(Color(.systemBackground))
                     }
                     .buttonStyle(.plain)
+                    .accessibilityIdentifier(AccessibilityID.Export.rangeButton(range.rawValue))
 
                     if range != DateRange.allCases.last {
                         Divider()
@@ -293,6 +297,7 @@ struct ExportView: View {
             .clipShape(RoundedRectangle(cornerRadius: 14))
         }
         .disabled(isExporting || validEntries.isEmpty)
+        .accessibilityIdentifier(AccessibilityID.Export.exportButton)
         .padding(.top, 8)
     }