fix: back buttons missing router instance mapping and fix array structure in supabase route stops fetch

frontend/test-sb.mjs

@@ -0,0 +1,29 @@
+import { createClient } from '@supabase/supabase-js'
+
+const SUPABASE_URL = 'https://bjgixlugjzsccazdfmph.supabase.co'
+const SUPABASE_ANON_KEY = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZSIsInJlZiI6ImJqZ2l4bHVnanpzY2NhemRmbXBoIiwicm9sZSI6ImFub24iLCJpYXQiOjE3NzIwNjQyMTAsImV4cCI6MjA4NzY0MDIxMH0.untLQoPi4yUr3cPnxo23wYSlg6xnNK0daKu9UHmFTp8'
+const sb = createClient(SUPABASE_URL, SUPABASE_ANON_KEY)
+
+async function test() {
+    console.log("Fetching a route and a bus stop to link...");
+    const { data: route } = await sb.from('routes').select('id').limit(1);
+    const { data: stop } = await sb.from('bus_stops').select('id').limit(1);
+
+    if (route?.[0] && stop?.[0]) {
+        console.log("Upserting route_stop link...");
+        const res = await sb.from('route_stops').upsert([{
+            route_id: route[0].id,
+            stop_id: stop[0].id,
+            stop_order: 1
+        }]).select()
+        console.log("Insert response:", JSON.stringify(res, null, 2))
+
+        console.log("Testing join...")
+        const { data, error } = await sb.from('route_stops').select('*, bus_stops(*)')
+        console.log('Join Data:', JSON.stringify(data?.[0], null, 2))
+        console.log('Join Error:', error)
+    } else {
+        console.log("No existing route or stop to link.")
+    }
+}
+test()