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>

package-lock.json

@@ -1,13 +1,16 @@
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   "packages": {
     "": {
       "name": "dj-visualizer",
-      "version": "1.4.1",
+      "version": "1.5.1",
       "license": "MIT",
+      "dependencies": {
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         "electron-builder": "^24.13.3"
@@ -485,6 +488,12 @@
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