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>

routes/meshtastic.py

@@ -11,21 +11,19 @@ Supports multiple connection types:
 from __future__ import annotations
 
 import queue
-import time
-from typing import Generator
 
-from flask import Blueprint, jsonify, request, Response
+from flask import Blueprint, Response, jsonify, request
 
-from utils.responses import api_success, api_error
 from utils.logging import get_logger
-from utils.sse import sse_stream_fanout
 from utils.meshtastic import (
+    MeshtasticMessage,
     get_meshtastic_client,
+    is_meshtastic_available,
     start_meshtastic,
     stop_meshtastic,
-    is_meshtastic_available,
-    MeshtasticMessage,
 )
+from utils.responses import api_error
+from utils.sse import sse_stream_fanout
 
 logger = get_logger('intercept.meshtastic')