Sankofa Journal Step 3: Real Views

Replace the placeholder views with real ones. The index lists posts, the detail page shows one and uses get_object_or_404, and the tag and author views filter. Use hard-coded Python lists of dictionaries for now, because the models do not exist until module 5 and the view logic is worth getting right on its own. Then deliberately request a post id that does not exist and confirm you get a clean 404 rather than a stack trace.