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_subghz.py

@@ -4,14 +4,11 @@ from __future__ import annotations
 
 import json
 import os
-import subprocess
-import tempfile
-from pathlib import Path
-from unittest.mock import patch, MagicMock
+from unittest.mock import MagicMock, patch
 
 import pytest
 
-from utils.subghz import SubGhzManager, SubGhzCapture
+from utils.subghz import SubGhzCapture, SubGhzManager
 
 
 @pytest.fixture
@@ -32,7 +29,7 @@ def manager(tmp_data_dir):
 class TestSubGhzManagerInit:
     def test_creates_data_dirs(self, tmp_path):
         data_dir = tmp_path / 'new_subghz'
-        mgr = SubGhzManager(data_dir=data_dir)
+        SubGhzManager(data_dir=data_dir)
         assert (data_dir / 'captures').is_dir()
 
     def test_active_mode_idle(self, manager):