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/notify.py

@@ -21,7 +21,7 @@ import smtplib
 import subprocess
 import time
 import sys
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Optional
 
 from . import data
@@ -49,6 +49,7 @@ logf = None
 
 _LEVEL_ORDER = {"RECOVER": 0, "INFO": 0, "WARNING": 1, "CRITICAL": 2}
 
+
 def _level_value(level: str) -> int:
     return _LEVEL_ORDER.get(level.upper(), 0)
 
@@ -103,7 +104,6 @@ def initlog(logfile):
 
 
 def closelog():
-    global logf
     if logf and logf != sys.stderr:
         try:
             logf.close()
@@ -331,8 +331,6 @@ async def _send_sms_voipms_async(channel_cfg: dict, notif: Notification) -> bool
         return False
 
 
-
-
 async def _send_matrix_async(channel_cfg: dict, notif: Notification) -> bool:
     """Send a Matrix message using matrix-nio."""
     try:
@@ -341,7 +339,6 @@ async def _send_matrix_async(channel_cfg: dict, notif: Notification) -> bool:
         logger.error("matrix-nio not installed; pip install matrix-nio")
         return False
 
-    from nio import AsyncClient
     homeserver = channel_cfg.get("homeserver", "")
     access_token = channel_cfg.get("access_token", "")
     room_id = channel_cfg.get("room_id", "")
@@ -359,7 +356,6 @@ async def _send_matrix_async(channel_cfg: dict, notif: Notification) -> bool:
     client = AsyncClient(homeserver)
     client.access_token = access_token
     try:
-        from nio import RoomSendResponse
         content = {
             "msgtype": "m.text",
             "body": text,