style: clear whitespace, unused-import and blank-line lint

Strip trailing whitespace, drop unused imports/variables/global statements,
split multi-imports, fix E3xx/E1xx spacing and E712 comparisons. No behaviour
change; only E501 long lines remain in flake8.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

hbd/server/udp.py

@@ -23,14 +23,14 @@ _STALE_INTERVAL_MULTIPLIER = 3
 
 # SO_TIMESTAMP: kernel attaches a struct timeval to each received datagram.
 # Supported on Linux, FreeBSD, and macOS.  The constant is not exposed by
-# Python's socket module on all platforms 
+# Python's socket module on all platforms
 platform = platform_system()
 if platform == "Darwin":
     _SO_TIMESTAMP = 1024  # SO_TIMESTAMP on macOS (not in Python's socket module)
 elif platform == "Linux":
     _SO_TIMESTAMP = 29  # Linux value (not in older Python versions)
 elif platform == "FreeBSD":
-     _SO_TIMESTAMP = 32  # FreeBSD value (not in older Python versions)
+    _SO_TIMESTAMP = 32  # FreeBSD value (not in older Python versions)
 else:
     logger.warning("SO_TIMESTAMP may not be supported on this platform (%s)", platform)
     _SO_TIMESTAMP = None
@@ -71,6 +71,7 @@ class RecvmsgTransport:
     Exposes the same sendto() / close() interface as asyncio's DatagramTransport
     so the rest of the code does not need to know which path is in use.
     """
+
     def __init__(self, loop, sock):
         self._loop = loop
         self._sock = sock
@@ -410,7 +411,7 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
     if not msg:
         return
     now = ctx.get("recv_ts") or time.time()
-    
+
     # Log message to journal
     msg_journal = ctx.get("msg_journal")
     if msg_journal:
@@ -421,7 +422,7 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
             loop.create_task(msg_journal.log_message(msg, addr, now))
         except Exception as e:
             logger.debug(f"Failed to log message to journal: {e}")
-    
+
     # Only named HTB/PLG datagrams come from clients; anything else (e.g. an internet scanner's
     # SIP probe) is journaled above but must not sign on a host.
     if msg.get("ID") not in ("HTB", "PLG") or not msg.get("name"):
@@ -432,7 +433,6 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
     hbdcls = ctx.get("hbdclass")
     msg_to_websockets = ctx.get("msg_to_websockets")
     DEBUG = ctx.get("DEBUG", 0)
-    verbose = ctx.get("verbose", False)
 
     # normalize addr (ip, port)
     ip = addr[0] if isinstance(addr, (list, tuple)) else addr
@@ -457,7 +457,7 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
     else:
         host = hbdcls.Host.hosts[uname]
         newh = False
-    
+
     cid = msg.get("id", 0)
     try:
         rtt = float(msg.get("rtt"))
@@ -523,14 +523,14 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
 
             # If os_info reports an owner and none is configured server-side, apply it
             if plugin_name == "os_info":
-                config_owner =  config_mod.get_host_access(cfg, uname).get("owner")
+                config_owner = config_mod.get_host_access(cfg, uname).get("owner")
                 default_owner = config_mod.get_default_owner(cfg)
                 inferred_owner = config_owner or plugin_data.get("owner") or default_owner
                 host.owner = inferred_owner
                 logger.info(f"owner for {uname} is {host.owner}")
             if DEBUG > 1:
                 print(f"Stored plugin data for {uname}: {plugin_name}")
-            
+
             # Check thresholds if checker is available
             threshold_checker = ctx.get("threshold_checker")
             if threshold_checker:
@@ -545,7 +545,7 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
                         print(f"Threshold state changes for {uname}: {state_changes}")
                 except Exception as e:
                     logger.error(f"Error checking thresholds for {uname}.{plugin_name}: {e}")
-            
+
             # Notify websockets of plugin update
             if msg_to_websockets:
                 try:
@@ -671,13 +671,13 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
         timeout_seconds = interval + grace
         on_overdue, _ = _make_timer_callbacks(uname, host, ctx)
         conn.reset_overdue_timer(timeout_seconds, on_overdue)
-    
+
     # Check RTT thresholds using the threshold checker
     threshold_checker = ctx.get("threshold_checker")
     if threshold_checker and rtt and rtt > 0:
         # Metric path for RTT is simply "rtt"
         metric_path = "rtt"
-        
+
         # Check against configured thresholds (handles alerts, notifications, etc.)
         threshold_checker.check_value(
             host_name=uname,