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/sstv_general.py

@@ -6,18 +6,17 @@ frequencies used by amateur radio operators worldwide.
 
 from __future__ import annotations
 
+import contextlib
 import queue
-import time
-from collections.abc import Generator
 from pathlib import Path
 
 from flask import Blueprint, Response, jsonify, request, send_file
 
-from utils.responses import api_success, api_error
 import app as app_module
-from utils.logging import get_logger
-from utils.sse import sse_stream_fanout
 from utils.event_pipeline import process_event
+from utils.logging import get_logger
+from utils.responses import api_error
+from utils.sse import sse_stream_fanout
 from utils.sstv import (
     get_general_sstv_decoder,
 )
@@ -325,7 +324,5 @@ def decode_file():
         return api_error(str(e), 500)
 
     finally:
-        try:
+        with contextlib.suppress(Exception):
             Path(tmp_path).unlink()
-        except Exception:
-            pass