Venues: persistent room, motivated camera, ride; drop Pylon Grid

- Venue as one continuous place: persistent per-song layer, interpolated
  venueState, story jumps (one re-hang max + recap) with camera cuts
- Room camera shot plan (venueShots.js): per-section size/target, monotonic
  look sweep, traverse glide body, room-side alternation
- New Ride venue: generated vehicle + actor passengers, radio RTT screen,
  chase/stationary modes, ride archetype across generator/camera/staging
- Flora cost trim (5x(12+6+6) -> 4x(8+4+4) SDF evals, 204ms -> 140ms worst)
- Delete Pylon Grid shader (2.5s/frame SwiftShader); drop its metadata row
- tools/venue-check.js headless gate harness + venue-gallery explorer

flow-state/filmstrip.html

@@ -114,6 +114,7 @@ const params = new URLSearchParams(location.search);
 const every = Number(params.get('every')) || DEFAULT_EVERY;
 const duration = Number(params.get('duration')) || DEFAULT_DURATION;
 const only = params.get('song') ? params.get('song').split(',') : null;
+const venueEnabled = params.get('venue') === '1';
 
 document.getElementById('everyLabel').textContent = every;
 
@@ -231,7 +232,7 @@ function summarise(built) {
 
 // The cache key carries the sampling parameters as well as the source, so
 // changing `?every=` does not silently show you the previous spacing's pixels.
-const cacheKey = () => `filmstrip:${every}:${duration}:${only ? only.join(',') : 'all'}:${sourceFingerprint()}`;
+const cacheKey = () => `filmstrip:${every}:${duration}:${only ? only.join(',') : 'all'}:v${venueEnabled ? 1 : 0}:${sourceFingerprint()}`;
 
 async function build() {
     bar.classList.add('building');
@@ -241,7 +242,7 @@ async function build() {
 
     const total = (only || songNames()).length;
     const built = await buildFilmstrip({
-        duration, every, names: only,
+        duration, every, names: only, venueEnabled,
         // Painted as they land, in bank order, rather than after the whole run.
         // A full build is a couple of minutes of GPU work and the interesting
         // failure — a strip whose frames could be shuffled — is visible in the