Body tracking: head/hands/feet drive the interactive families

MediaPipe PoseLandmarker (BlazePose lite) integrated fully offline: the
WASM runtime and the bundled .task model are served to the renderer over
a new djvres:// protocol (fetch does not work on file://), with
'wasm-unsafe-eval' added to the output CSP. pose.js exposes PoseTracker;
interactive.js detects at ~30 Hz, maps landmarks into mirrored
cover-fitted screen space and smooths them with velocities.

Upgrades when a body is tracked (silent fallback to motion otherwise):
- all physical modes: moving head/hands/feet stamp precise motion blobs
- Sciame: the swarm follows your head
- Interattivo Modello: hand swipes spin the robot, it leans toward your
  head, raising a hand fast makes it jump
- Silhouette: neon skeleton (bones + joints + glowing head) over the
  electric outline

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/output.html

@@ -3,7 +3,7 @@
 <head>
   <meta charset="UTF-8" />
   <meta http-equiv="Content-Security-Policy"
-        content="default-src 'self'; img-src 'self' blob: data: file:; media-src 'self' blob: file:; style-src 'self' 'unsafe-inline'; script-src 'self'" />
+        content="default-src 'self'; img-src 'self' blob: data: file:; media-src 'self' blob: file:; style-src 'self' 'unsafe-inline'; script-src 'self' djvres: 'wasm-unsafe-eval'; connect-src 'self' djvres:" />
   <title>DJ Visualizer — Output</title>
   <link rel="stylesheet" href="style.css" />
 </head>
@@ -46,6 +46,8 @@
   <script src="shaders.js"></script>
   <script src="effects.js"></script>
   <script src="fluid.js"></script>
+  <script src="../node_modules/@mediapipe/tasks-vision/vision_bundle.js"></script>
+  <script src="pose.js"></script>
   <script src="interactive.js"></script>
   <script src="model3d.js"></script>
   <script src="visualizer.js"></script>