feat(espnow): Pi bridge client, binary wire, and espnow-sender firmware

Replace serial/Wi-Fi driver transport paths with WebSocket bridge client,
binary espnow_wire delivery, device announce registry, and restructured
espnow-sender (AP + broadcast passthrough). Includes docs and tests.

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

src/controllers/preset.py

@@ -7,6 +7,7 @@ from models.device import Device, normalize_mac
 from models.transport import get_current_sender
 from util.driver_delivery import deliver_json_messages, deliver_preset_broadcast_then_per_device
 from util.espnow_message import build_message, build_preset_dict
+from util.binary_driver_messages import build_preset_cmd_chunks
 from util.profile_bundle import export_preset_bundle, import_preset_bundle
 import json
 
@@ -225,39 +226,13 @@ async def send_presets(request, session):
     if not sender:
         return json.dumps({"error": "Transport not configured"}), 503, {'Content-Type': 'application/json'}
 
-    MAX_BYTES = 240
     send_delay_s = 0.1
-    entries = list(presets_by_name.items())
-    total_presets = len(entries)
-
-    batch = {}
-    chunk_messages = []
-    for name, preset_obj in entries:
-        test_batch = dict(batch)
-        test_batch[name] = preset_obj
-        test_msg = build_message(presets=test_batch, save=save_flag, default=default_id)
-        size = len(test_msg)
-
-        if size <= MAX_BYTES or not batch:
-            batch = test_batch
-        else:
-            chunk_messages.append(
-                build_message(
-                    presets=dict(batch),
-                    save=False,
-                    default=None,
-                )
-            )
-            batch = {name: preset_obj}
-
-    if batch:
-        chunk_messages.append(
-            build_message(
-                presets=dict(batch),
-                save=save_flag,
-                default=default_id,
-            )
-        )
+    total_presets = len(presets_by_name)
+    chunk_messages = build_preset_cmd_chunks(
+        presets_by_name,
+        save=save_flag,
+        default=str(default_id) if default_id is not None else None,
+    )
 
     target_list = None
     raw_targets = data.get("targets")