feat(web): two-pane "cockpit" redesign with a live board rail

Restructure the workshop flow into the designer's cockpit: a persistent shell
(header + 5-step stepper + sticky instrument rail) wrapping the phase routes via
a React-Router layout route, so the rail stays mounted across navigation.

- Design system: IBM Plex Mono + Newsreader; the full cockpit token set (light
  + dark) in index.css; a working light/dark theme toggle (store `theme` +
  useApplyTheme); a `switch` ui primitive.
- Shell: CockpitLayout, Stepper (forward-gated), PanelChrome helpers. Every
  phase page restyled to the editorial panels + the WORKSHOP-FLOW fixes
  (channels-after-bind, domain framing + L1 prefill, L2/L3 prefill at 3/3,
  in-place submission finale). Store gains `tried` + `channels.saidHi` (v4).
- Live rail (CockpitRail): real node heartbeat + agent activity log + ADD
  progress; sim telemetry (useTelemetry) for the waveform/accel/I2C behind a
  seam, marked SIM.
- LED-matrix PIXEL MIRROR (real): the rail shows exactly what the physical
  matrix displays — API GET /nodes/:team/matrix reads the board's framebuffer
  off the :9999 relay (readMatrixFrame + the `matrixget` relay command);
  useMatrixMirror polls it and unpacks the 104 bits.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

deploy/uno-q/matrix-relay/relay.py

@@ -37,6 +37,9 @@ def handle(conn):
         elif cmd == "count" and len(parts) >= 2:
             Bridge.call("matrix_count", int(parts[1]))
             conn.sendall(b"ok\n")
+        elif cmd == "matrixget":
+            r = Bridge.call("matrix_get")
+            conn.sendall(f"{r}\n".encode())
         elif cmd == "i2c":
             r = Bridge.call("i2c_scan")
             conn.sendall(f"{r}\n".encode())