v2.26.0: fix SSE fanout crash and branded logo FOUC

- Fix SSE fanout thread AttributeError when source queue is None during
  interpreter shutdown by snapshotting to local variable with null guard
- Fix branded "i" logo rendering oversized on first page load (FOUC) by
  adding inline width/height to SVG elements across 10 templates
- Bump version to 2.26.0 in config.py, pyproject.toml, and CHANGELOG.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_weather_sat_decoder.py

@@ -6,20 +6,16 @@ and image handling.
 
 from __future__ import annotations
 
-import os
-import tempfile
-import threading
 import time
 from datetime import datetime, timezone
 from pathlib import Path
-from unittest.mock import patch, MagicMock, call, mock_open
-import pytest
+from unittest.mock import MagicMock, patch
 
 from utils.weather_sat import (
+    WEATHER_SATELLITES,
+    CaptureProgress,
     WeatherSatDecoder,
     WeatherSatImage,
-    CaptureProgress,
-    WEATHER_SATELLITES,
     get_weather_sat_decoder,
     is_weather_sat_available,
 )