Clean up: drop unused imports, tighten test exception assert

- Remove unused utcnow / HopEdge imports (F401).
- Assert DeviceCommandError instead of bare Exception in the admin-login test (B017).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

meshtools/core/connection.py

@@ -18,7 +18,7 @@ import random
 from abc import ABC, abstractmethod
 from typing import Optional
 
-from .models import Contact, Hop, TraceResult, utcnow
+from .models import Contact, Hop, TraceResult
 
 TX_POWER_MIN = 1
 TX_POWER_MAX = 22

meshtools/ui/widgets.py

@@ -22,7 +22,6 @@ from ..core.models import (
     LOCAL_DEVICE_LABEL,
     Contact,
     HopAggregate,
-    HopEdge,
     TraceResult,
     TraceStats,
     TxOptResult,

tests/test_skeleton.py

@@ -9,7 +9,7 @@ from pathlib import Path
 
 import pytest
 
-from meshtools.core.connection import MockDevice, clamp_tx_power
+from meshtools.core.connection import DeviceCommandError, MockDevice, clamp_tx_power
 from meshtools.core.models import Contact, TraceResult, TraceStats
 from meshtools.persistence.repository import Repository
 from meshtools.services import trace_runner
@@ -274,7 +274,7 @@ async def test_admin_login_rejects_wrong_password() -> None:
     admin = (await device.get_contacts())[0]
 
     assert await device.admin_login(admin, "nope") is False
-    with pytest.raises(Exception):
+    with pytest.raises(DeviceCommandError):
         await device.set_remote_tx_power(admin, 18)  # not logged in
     assert await device.admin_login(admin, "secret") is True
     await device.set_remote_tx_power(admin, 18)  # now allowed