refactor: companion FrameServer and related (substantive only, no Black)

Reapply refactor from ce8381a (replace monolithic FrameServer with thin
pymc_core subclass, re-export constants, SQLite persistence hooks) while
preserving pre-refactor whitespace where patch applied cleanly. Remaining
files match refactor commit exactly. Diff vs ce8381a is whitespace-only.

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

repeater/handler_helpers/protocol_request.py

@@ -10,12 +10,12 @@ import struct
 import time
 
 from pymc_core.node.handlers.protocol_request import (
-    ProtocolRequestHandler,
-    REQ_TYPE_GET_STATUS,
-    REQ_TYPE_GET_TELEMETRY_DATA,
     REQ_TYPE_GET_ACCESS_LIST,
     REQ_TYPE_GET_NEIGHBOURS,
-    SERVER_RESPONSE_DELAY_MS
+    REQ_TYPE_GET_STATUS,
+    REQ_TYPE_GET_TELEMETRY_DATA,
+    SERVER_RESPONSE_DELAY_MS,
+    ProtocolRequestHandler,
 )
 
 logger = logging.getLogger("ProtocolRequestHelper")
@@ -23,8 +23,16 @@ logger = logging.getLogger("ProtocolRequestHelper")
 
 class ProtocolRequestHelper:
     """Provides repeater-specific protocol request handlers."""
-    
-    def __init__(self, identity_manager, packet_injector=None, acl_dict=None, radio=None, engine=None, neighbor_tracker=None):
+
+    def __init__(
+        self,
+        identity_manager,
+        packet_injector=None,
+        acl_dict=None,
+        radio=None,
+        engine=None,
+        neighbor_tracker=None,
+    ):
 
         self.identity_manager = identity_manager
         self.packet_injector = packet_injector
@@ -71,9 +79,10 @@ class ProtocolRequestHelper:
         }
         
         logger.info(f"Registered protocol request handler for '{name}': hash=0x{hash_byte:02X}")
-    
+
     def _create_acl_contacts_wrapper(self, acl):
         """Create contacts wrapper from ACL."""
+
         class ACLContactsWrapper:
             def __init__(self, identity_acl):
                 self._acl = identity_acl
@@ -138,22 +147,32 @@ class ProtocolRequestHelper:
         # uint32_t n_direct_dups;
         # uint32_t n_flood_dups;
         # uint32_t total_rx_air_time_secs;
-        
+
         # Get stats from radio/engine
         noise_floor = int(self.radio.get_noise_floor() * 1.0) if self.radio else -120
-        last_rssi = int(self.radio.last_rssi) if self.radio and hasattr(self.radio, 'last_rssi') else -120
-        last_snr = int((self.radio.last_snr * 4.0) if self.radio and hasattr(self.radio, 'last_snr') else 0)
-        
+        last_rssi = (
+            int(self.radio.last_rssi) if self.radio and hasattr(self.radio, "last_rssi") else -120
+        )
+        last_snr = int(
+            (self.radio.last_snr * 4.0) if self.radio and hasattr(self.radio, "last_snr") else 0
+        )
+
         # Get packet counts
-        n_packets_recv = self.radio.packets_received if self.radio and hasattr(self.radio, 'packets_received') else 0
-        n_packets_sent = self.radio.packets_sent if self.radio and hasattr(self.radio, 'packets_sent') else 0
-        
+        n_packets_recv = (
+            self.radio.packets_received
+            if self.radio and hasattr(self.radio, "packets_received")
+            else 0
+        )
+        n_packets_sent = (
+            self.radio.packets_sent if self.radio and hasattr(self.radio, "packets_sent") else 0
+        )
+
         # Get airtime stats
         total_air_time_secs = 0
         total_rx_air_time_secs = 0
-        if self.engine and hasattr(self.engine, 'airtime_manager'):
+        if self.engine and hasattr(self.engine, "airtime_manager"):
             total_air_time_secs = int(self.engine.airtime_manager.total_tx_airtime_ms / 1000)
-        
+
         # Get routing stats
         n_sent_flood = 0
         n_sent_direct = 0
@@ -161,18 +180,18 @@ class ProtocolRequestHelper:
         n_recv_direct = 0
         n_direct_dups = 0
         n_flood_dups = 0
-        
+
         if self.engine:
-            n_sent_flood = getattr(self.engine, 'sent_flood_count', 0)
-            n_sent_direct = getattr(self.engine, 'sent_direct_count', 0)
-            n_recv_flood = getattr(self.engine, 'recv_flood_count', 0)
-            n_recv_direct = getattr(self.engine, 'recv_direct_count', 0)
-            n_direct_dups = getattr(self.engine, 'direct_dup_count', 0)
-            n_flood_dups = getattr(self.engine, 'flood_dup_count', 0)
-        
+            n_sent_flood = getattr(self.engine, "sent_flood_count", 0)
+            n_sent_direct = getattr(self.engine, "sent_direct_count", 0)
+            n_recv_flood = getattr(self.engine, "recv_flood_count", 0)
+            n_recv_direct = getattr(self.engine, "recv_direct_count", 0)
+            n_direct_dups = getattr(self.engine, "direct_dup_count", 0)
+            n_flood_dups = getattr(self.engine, "flood_dup_count", 0)
+
         # Pack struct (little-endian)
         stats = struct.pack(
-            '<HHhhIIIIIIIIIhIII',
+            "<HHhhIIIIIIIIIhIII",
             0,  # batt_milli_volts (not available on Pi)
             0,  # curr_tx_queue_len (TODO)
             noise_floor,