feat(intro): v2 — cities, accelerating sweep, detections, thriller sound design

- City engine: Esri ground, OSM buildings that rise with the scan, road
  ribbons carrying modelled traffic coloured by congestion, NYC DOT cameras,
  real ADS-B, MBTA GTFS lines + realtime vehicles, LAX runways with approach
  strobes, Fort Bragg restricted volumes, Everest terrain with contours.
- Indexing keeps accelerating into a 260-capture global sweep while the
  planet whips a full turn.
- The eye opens: aperture blades, sensor array waking, optics calibration,
  radar sweep, orbiting coordinate ring.
- Camera wall with YOLOv8n detections and a city-pulse trace.
- Ends on GOD'S EYE VIEW / OMNISCIENCE.
- audio/sfx.py: sound design only, built to sit under a music track.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01KqP857pippaUs6konSDfe8

intro-sequence/tools/live/common.py

@@ -0,0 +1,15 @@
+import math
+SCENES = {
+    'nyc': (40.7400, -73.9900, 3500),
+    'boston': (42.3555, -71.0605, 3200),
+    'lax': (33.9425, -118.4081, 3500),
+    'bragg': (35.1580, -79.0090, 6000),
+}
+def enu(slug, lat, lon):
+    lat0, lon0, _ = SCENES[slug]
+    x = (lon - lon0) * math.cos(math.radians(lat0)) * 111320
+    y = (lat - lat0) * 110540
+    return round(x, 1), round(y, 1)
+def inside(slug, x, y, margin=0.0):
+    h = SCENES[slug][2] + margin
+    return abs(x) <= h and abs(y) <= h