Add PCB routing timelapse video to README

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CDJ-MainBoard/CDJ-MainBoard.kicad_prl

@@ -1,6 +1,6 @@
 {
   "board": {
-    "active_layer": 0,
+    "active_layer": 6,
     "active_layer_preset": "",
     "auto_track_width": true,
     "hidden_netclasses": [],

CDJ-MainBoard/CDJ-MainBoard.kicad_pro

@@ -577,7 +577,7 @@
       "plot": "../../../Downloads/",
       "pos_files": "",
       "specctra_dsn": "",
-      "step": "",
+      "step": "../3d_models/2026-03-26_CDJ-MainBoard-v1_fully_routed.step",
       "svg": "",
       "vrml": ""
     },

README.md

@@ -2,6 +2,8 @@
 
 A custom CDJ (Compact Disc Jockey) unit built from scratch around a Raspberry Pi CM5, designed to run [Mixxx](https://mixxx.org/) DJ software. Features a custom PCB, a custom 3D-printed chassis, and reuses original CDJ buttons and jog wheel for an authentic DJ experience. Reads Rekordbox-formatted USB sticks — no laptop required.
 
+<video src="screenshots/pcb_routing_1min.mp4" autoplay loop muted playsinline></video>
+
 ![PCB 3D render](screenshots/pcb-3d-render.png)
 
 ## What is this?