Build an Instagram Clone App in Swift with AI

Build a polished, fully working native iOS app in SwiftUI named Pixgram: an original photo-sharing social app that recreates the core experience of Instagram, but with its own name, its own original logo and its own color palette. Do NOT use the Instagram name, logo, wordmark, app icon or any trademarked asset anywhere in the app. Design an original Pixgram logo mark, drawn with SwiftUI shapes (Path/Canvas) or made as a generated image asset, and use it in the header.

Screens and flows (bottom tab bar: Home, Explore, Create, Activity, Profile; light theme, white background, near-black text, accent gradient for story rings is your own sunset-coral to violet blend):
1. Home feed. Header: Pixgram wordmark in a script-style display font (a bundled .ttf or a drawn wordmark), a heart icon (opens Activity) and a paper-plane icon (opens Messages). Stories row: "Your story" with a + badge, then 9 friends with gradient rings and usernames. Feed of 8 posts: avatar, username, verified tick on two, location line, square or 4:5 photo, actions row (heart, comment, share, bookmark), "Liked by maya.lens and 1,284 others", caption with username bold and "more" expander, "View all 36 comments", "2 hours ago". One post is a 3-photo carousel with swipe and page dots and a "1/3" pill.
2. Likes: double-tap a photo shows a big white heart burst that pops and fades over the photo and likes the post; the heart icon fills red with a bounce, like count updates; tap again to unlike. Bookmark toggles filled.
3. Stories: tap a story ring to open a full-screen story viewer: segmented progress bars at the top that fill over 5 s and auto-advance, avatar + name + time, tap right half for next, left half for previous, it moves on to the next friend's stories at the end, swipe down or X to close, "Send message" reply bar with heart and send. Viewed rings turn grey in the stories row.
4. Comments: the comment icon opens a bottom sheet with 12 comments (avatars, likes on comments, reply links), an emoji quick bar and an input; posting adds your comment at the top with an animation.
5. Explore: search bar, 3-column photo grid with a few 2x2 tiles; tapping a tile opens that post in a scrollable feed. Typing in search shows matching accounts.
6. Create: pick a photo from a fixture gallery grid (12 photos), next to a caption screen, Share puts the new post at the top of Home with a short "Posted" toast.
7. Activity: "Today / This week" sections of likes, follows (Follow button toggles to Following) and comments.
8. Profile (ansh.shoots): avatar with story ring, posts / followers / following counts, name, bio with a link, Edit profile and Share profile buttons, story highlights row, grid / reels / tagged tabs, 3-column grid of 15 posts.
9. Messages: list of 8 chats with online dots; tap opens a thread with bubbles; sending a message appends it and the other person replies after a short typing indicator.

Rules for the whole app:
- Native SwiftUI for iOS 26, the deployment target the Vibecode iOS template already uses (do not change it). iPhone-first layout. SF Symbols are fine for UI icons (never for the Instagram logo or any brand mark).
- Everything runs on-device from realistic, deterministic fixture data in one Swift file (e.g. Fixtures.swift: real-sounding names, handles, numbers, timestamps, captions). No backend (leave the backend/ folder alone and make no network calls except loading images and media), no login, no permissions (no camera, photos, location, contacts, notifications, microphone). Do not persist state (no UserDefaults, @AppStorage, SwiftData or files): every launch starts from the same fixture state, so the demo is repeatable.
- Remote images: load images.unsplash.com photo URLs (with ?w=800&q=80 style params) with AsyncImage (or a small cached image view) and a tasteful placeholder. Verify every image and media URL with `curl -s -o /dev/null -w "%{http_code}" <url>` before you use it and replace any that do not return 200. No broken or blank images anywhere.
- Polish: native-feeling spacing and typography, safe areas, smooth spring animations (.spring/.snappy, most under 350 ms), matchedGeometryEffect for hero and expand/collapse transitions where it helps, .sensoryFeedback haptics on key taps, pressed states, and loading/empty states. Simulated waits stay short (under 3 s). Every button visible on screen does something sensible; nothing is a dead end.
- Keep the compiler happy: small files (under ~300 lines each), big view bodies split into subviews, and no long chained expressions, so nothing hits "unable to type-check this expression in reasonable time".
- It must build with zero errors and run in the iOS simulator with no crash. Walk through every flow above and fix anything broken.