docs(server): tighten the method-guard comments and changelog

server/providers/aircraft/opensky.js

@@ -496,10 +496,7 @@ export function openSkyProxy() {
         // This mount also matches its /track route, served by its own handler.
         if (new URL(req.url || '/', 'http://localhost').pathname !== '/')
           return next();
-        // Read-only snapshot endpoint: state the method contract the way
-        // /api/geocode and the other query proxies state it, rather than
-        // answering any verb with the same body and ignoring the request body.
-        // Checked after the /track hand-off, so that route keeps its own.
+        // After the /track hand-off, so /track keeps its own method handling.
         if (req.method !== 'GET') {
           res.writeHead(405, {
             'Content-Type': 'application/json',