Add /set: on-set screen tracking markers for crews

- Unlinked, noindex page listing marker PNGs from public/set/markers
  (discovered at build time; filenames encode device/resolution/orientation)
- Detects the current screen and offers the closest match first
- One-tap full-screen viewer: wake lock, hidden controls, full grid/edges
  toggle, fill vs fit by aspect, back button closes, deep links via hash
- Offline service worker + home-screen manifest for iPhone full screen
- Marketing chrome moved into an (site) route group so /set has none

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -21,6 +21,24 @@ All copy (studio info, services, projects, contact email) lives in
 - **Logo:** the fox mark is a vector in `components/Fox.tsx` / `public/fox.svg`,
   traced from `G:\_ADMIN\TWOTALESLOGO.png`. Favicons are `app/icon.png` and `app/apple-icon.png`.
 
+## On-set screen markers (`/set`)
+
+`twotalesvfx.com/set` is a tool page for production crews (not linked from the site,
+not indexed). It lists screen-tracking marker images, highlights the one matching the
+device it's opened on, and shows it full-screen in one tap. It works offline after the
+first visit.
+
+To add a device, drop PNGs into `public/set/markers/` named like:
+
+```
+markers_phone_iPhone-Pro_1179x2556.png                  # full dot grid
+edge-markers_phone_iPhone-Pro_2556x1179_landscape.png   # edges only
+markers_laptop_1920x1080.png                            # name is optional
+```
+
+Kinds: `phone`, `tablet`, `laptop`, `monitor`. Any other PNG shows under "Other".
+Bump `CACHE` in `public/set/sw.js` when replacing an existing image so phones fetch the new one.
+
 ## Structure
 
 ```