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/debug.html

@@ -78,6 +78,13 @@
                 <a href="/filmstrip.html?song=centre,ember">?song=</a> just these ·
                 <code>EPIC-4.md</code> for the arc it is checking</div>
         </div>
+        <div class="card fast">
+            <h3><a href="/venue-gallery.html">venue gallery</a></h3>
+            <p>Venue &times; viz explorer — venue (higher-level than viz, picked first via census; hybrid
+               projection per archetype) against viz behind it. Try a sad-slow chamber of memories vs. a
+               pumping stage field from different angles and with different viz.</p>
+            <div class="meta">rows = songs · try <code>?venue=1</code> in gallery/filmstrip/app</div>
+        </div>
         <div class="card fast">
             <h3><a href="/">the app</a></h3>
             <p>Drop a track and watch it. <code>test/songs/*.wav</code> holds the