dynamic banner width, hoist HTML escaper, cache CA, restore log path

- banner box width adapts to longest value (fixes overflow with long paths)
- hoist h() HTML escape function to script top, remove 3 local copies
- serve_ca: add Cache-Control: public, max-age=86400
- restore log path in dashboard footer alongside new config/data fields

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

src/api.rs

@@ -828,6 +828,7 @@ async fn serve_ca(State(ctx): State<Arc<ServerCtx>>) -> Result<impl IntoResponse
                 header::CONTENT_DISPOSITION,
                 "attachment; filename=\"numa-ca.pem\"",
             ),
+            (header::CACHE_CONTROL, "public, max-age=86400"),
         ],
         bytes,
     ))