fix(frontend): remove UTF-8 BOM from package.json — breaks vite build (0.20.26)

PostCSS config load failed with SyntaxError at position 0 on Linux deploy.

backend/tests/test_health.py

@@ -1,9 +1,9 @@
-"""Version and health contract smoke tests (no DB required)."""
+"""Version and health contract smoke tests (no DB required)."""
 
 from app.version import APP_NAME, APP_VERSION, APP_VERSION_LABEL
 
 
 def test_version_constants():
-    assert APP_VERSION == "0.20.25"
+    assert APP_VERSION == "0.20.26"
     assert APP_NAME == "Security Alert Center"
-    assert APP_VERSION_LABEL == "Security Alert Center v.0.20.25"
+    assert APP_VERSION_LABEL == "Security Alert Center v.0.20.26"