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>

tests/test_bridge_ws_client.py

@@ -20,7 +20,7 @@ def test_send_returns_false_when_not_connected():
     async def _run():
         client = BridgeWsClient("ws://127.0.0.1/ws", reconnect_delay_s=0.01)
 
-        async def _no_wait(_timeout=30.0):
+        async def _no_wait(timeout=30.0):
             return False
 
         client.wait_connected = _no_wait  # type: ignore[method-assign]