docs(espnow): update docs and tests for p2p merge

Align API, architecture, and help with devices envelope transport,
bridge wifi/serial settings, and MAC-keyed device registry. Fix
endpoint tests for envelope identify payloads; remove obsolete p2p.py.
Bump led-tool for --serial-usb bridge provisioning.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/SPECIFICATION.md

@@ -28,7 +28,7 @@
 The LED Driver system is a MicroPython-based application for controlling LED strips via ESP32-C3 microcontrollers. The system uses a custom firmware image with usqlite and microdot built-in as frozen modules. The system provides:
 
 - Real-time LED pattern control
-- Multi-device management via peer-to-peer communication (ESPNow)
+- Multi-device management via ESP-NOW (peer-to-peer on 2.4 GHz; Pi reaches drivers through a bridge ESP32)
 - Group-based device control
 - Web-based configuration interface
 - Binary message protocol for efficient communication
@@ -49,7 +49,7 @@ The LED Driver system is a MicroPython-based application for controlling LED str
 - Preset system for saving and loading pattern configurations
 - Profile and Scene system for complex lighting setups
 - Preset sequencing within groups for time-based transitions
-- Peer-to-peer communication via ESPNow
+- ESP-NOW peer-to-peer between bridge and led-driver devices; Pi ↔ bridge over WebSocket or USB serial
 - Binary message protocol for bandwidth efficiency
 - Persistent settings storage (usqlite database)
 - Web-based configuration interface (Microdot web server)