Fix iOS widget date formatting for RFC3339 dates

- Add centralized formatWidgetDate() helper that handles both yyyy-MM-dd and ISO8601 formats
- Update widget date display to show "Today", "in X days", or "X days ago"
- Fix isTaskOverdue() to parse ISO8601 dates from Go API
- Remove duplicate date formatting functions from widget views
- Switch API environment back to DEV

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

iosApp/iosApp/Helpers/WidgetDataManager.swift

@@ -150,15 +150,32 @@ final class WidgetDataManager {
     private func isTaskOverdue(dueDate: String?, status: String?) -> Bool {
         guard let dueDateStr = dueDate else { return false }
 
-        let formatter = DateFormatter()
-        formatter.dateFormat = "yyyy-MM-dd"
+        var date: Date?
 
-        guard let date = formatter.date(from: dueDateStr) else { return false }
+        // Try parsing as yyyy-MM-dd first
+        let dateOnlyFormatter = DateFormatter()
+        dateOnlyFormatter.dateFormat = "yyyy-MM-dd"
+        date = dateOnlyFormatter.date(from: dueDateStr)
+
+        // Try parsing as ISO8601 (RFC3339) if that fails
+        if date == nil {
+            let isoFormatter = ISO8601DateFormatter()
+            isoFormatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+            date = isoFormatter.date(from: dueDateStr)
+
+            // Try without fractional seconds
+            if date == nil {
+                isoFormatter.formatOptions = [.withInternetDateTime]
+                date = isoFormatter.date(from: dueDateStr)
+            }
+        }
+
+        guard let parsedDate = date else { return false }
 
         // Task is overdue if due date is in the past and status is not completed
         let statusLower = status?.lowercased() ?? ""
         let isCompleted = statusLower == "completed" || statusLower == "done"
 
-        return !isCompleted && date < Calendar.current.startOfDay(for: Date())
+        return !isCompleted && parsedDate < Calendar.current.startOfDay(for: Date())
     }
 }