perf: add Server-Timing, split fitness bundle, tighten DB queries

- Add `timing` handle in hooks.server.ts emitting Server-Timing headers
  and expose `locals.timing.mark/measure` for per-load instrumentation.
- Drop dead `getEnrichedExerciseById` fallback in fitness detail page —
  server load already 404s via errorWithVerse, so the client no longer
  pulls exercisedb-raw.json (~760KB) into the detail bundle.
- Add `{ createdBy: 1, nextExecutionDate: -1 }` index on RecurringPayment
  for user-scoped list queries.
- Narrow populate projections in cospend/debts (title/date/category on
  userSplits, _id only on allRelatedSplits) to cut payload + hydration.
- Parallelize today's sessions + WorkoutSchedule lookup in the nutrition
  page load via Promise.all; add `.lean()` + `.select('templateId')` to
  the lastScheduled query.

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "homepage",
-	"version": "1.37.2",
+	"version": "1.37.3",
 	"private": true,
 	"type": "module",
 	"scripts": {

src/app.d.ts

@@ -13,6 +13,10 @@ declare global {
 		interface Locals {
 			auth(): Promise<Session | null>;
 			session?: Session | null;
+			timing: {
+				mark(name: string, dur: number): void;
+				measure<T>(name: string, fn: () => Promise<T> | T): Promise<T>;
+			};
 		}
 		// interface PageData {}
 		interface PageState {

src/hooks.server.ts

@@ -6,6 +6,31 @@ import { initializeScheduler } from "./lib/server/scheduler"
 import { dbConnect } from "./utils/db"
 import { errorWithVerse, getRandomVerse } from "$lib/server/errorQuote"
 
+async function timing({ event, resolve }: Parameters<Handle>[0]) {
+	const marks: Record<string, number> = {};
+	event.locals.timing = {
+		mark(name, dur) {
+			marks[name] = (marks[name] ?? 0) + dur;
+		},
+		async measure(name, fn) {
+			const t0 = performance.now();
+			try {
+				return await fn();
+			} finally {
+				this.mark(name, performance.now() - t0);
+			}
+		}
+	};
+	const t0 = performance.now();
+	const response = await resolve(event);
+	marks.total = performance.now() - t0;
+	const header = Object.entries(marks)
+		.map(([k, v]) => `${k};dur=${v.toFixed(1)}`)
+		.join(', ');
+	response.headers.set('Server-Timing', header);
+	return response;
+}
+
 // Initialize database connection on server startup
 console.log('🚀 Server starting - initializing database connection...');
 await dbConnect().then(() => {
@@ -19,7 +44,7 @@ await dbConnect().then(() => {
 });
 
 async function authorization({ event, resolve }: Parameters<Handle>[0]) {
-	const session = await event.locals.auth();
+	const session = await event.locals.timing.measure('auth', () => event.locals.auth());
 	event.locals.session = session;
 	const { fetch, url } = event;
 
@@ -107,6 +132,7 @@ export const handleError: HandleServerError = async ({ error, event, status, mes
 };
 
 export const handle: Handle = sequence(
+	timing,
 	auth.handle,
 	authorization
 );

src/models/RecurringPayment.ts

@@ -137,5 +137,6 @@ const RecurringPaymentSchema = new mongoose.Schema(
 
 // Index for efficiently finding payments that need to be executed
 RecurringPaymentSchema.index({ nextExecutionDate: 1, isActive: 1 });
+RecurringPaymentSchema.index({ createdBy: 1, nextExecutionDate: -1 });
 
 export const RecurringPayment = mongoose.model<IRecurringPayment>("RecurringPayment", RecurringPaymentSchema);

src/routes/api/cospend/debts/+server.ts

@@ -31,7 +31,7 @@ export const GET: RequestHandler = async ({ locals }) => {
   try {
     // Get all splits for the current user
     const userSplits = await PaymentSplit.find({ username: currentUser })
-      .populate('paymentId')
+      .populate('paymentId', 'title date category _id')
       .lean();
 
     // Get all other users who have splits with payments involving the current user
@@ -40,7 +40,7 @@ export const GET: RequestHandler = async ({ locals }) => {
       paymentId: { $in: paymentIds } as any,
       username: { $ne: currentUser }
     })
-      .populate('paymentId')
+      .populate('paymentId', '_id')
       .lean();
 
     // Group debts by user

src/routes/fitness/[exercises=fitnessExercises]/[id]/+page.svelte

@@ -1,6 +1,5 @@
 <script>
 	import { page } from '$app/stores';
-	import { getEnrichedExerciseById } from '$lib/data/exercisedb';
 
 	/** @param {string | undefined | null} type @param {'en'|'de'} lang */
 	function exerciseTypeInfo(type, lang) {
@@ -20,7 +19,6 @@
 				return null;
 		}
 	}
-	import { localizeExercise, translateTerm } from '$lib/data/exercises';
 	import { detectFitnessLang, fitnessSlugs, t } from '$lib/js/fitnessI18n';
 	import { ChevronRight } from '@lucide/svelte';
 
@@ -54,7 +52,7 @@
 
 	let activeTab = $state('about');
 
-	const exercise = $derived(data.exercise ?? getEnrichedExerciseById($page.params.id, lang));
+	const exercise = $derived(data.exercise);
 	const typeInfo = $derived(exerciseTypeInfo(exercise?.exerciseType, lang));
 	const similar = $derived(data.similar ?? []);
 	const history = $derived(data.history?.history ?? []);

src/routes/fitness/[nutrition=fitnessNutrition]/[[date=fitnessDate]]/+page.server.ts

@@ -19,10 +19,13 @@ export const load: PageServerLoad = async ({ fetch, params, locals }) => {
 		try {
 			const user = await requireAuth(locals);
 			await dbConnect();
-			const sessions = await WorkoutSession.find({
-				createdBy: user.nickname,
-				startTime: { $gte: dayStart, $lte: dayEnd }
-			}).select('kcalEstimate').lean();
+			const [sessions, schedule] = await Promise.all([
+				WorkoutSession.find({
+					createdBy: user.nickname,
+					startTime: { $gte: dayStart, $lte: dayEnd }
+				}).select('kcalEstimate').lean(),
+				WorkoutSchedule.findOne({ userId: user.nickname }).lean()
+			]);
 			let kcal = 0;
 			for (const s of sessions) {
 				if (s.kcalEstimate?.kcal) kcal += s.kcalEstimate.kcal;
@@ -31,12 +34,11 @@ export const load: PageServerLoad = async ({ fetch, params, locals }) => {
 			// If no exercise done today, project kcal from the next scheduled template
 			let projected = null;
 			if (kcal === 0) {
-				const schedule = await WorkoutSchedule.findOne({ userId: user.nickname });
 				if (schedule?.templateOrder?.length) {
 					const lastScheduled = await WorkoutSession.findOne({
 						createdBy: user.nickname,
 						templateId: { $in: schedule.templateOrder }
-					}).sort({ startTime: -1 });
+					}).sort({ startTime: -1 }).select('templateId').lean();
 
 					let nextId;
 					if (!lastScheduled?.templateId) {