refactor: migrate hrefs to resolve()/asset() from $app/paths

Replace string-literal and template-literal hrefs across the codebase
with the modern SvelteKit 2.26+ resolve() and asset() APIs. Migration
makes route IDs explicit, type-checked against generated $app/types,
and base-path-aware. Two codemod scripts handle the bulk; remaining
ambiguous, query-bearing, and precomputed-href cases are converted
manually at the assignment sites.

src/lib/components/cospend/PaymentModal.svelte

@@ -1,4 +1,5 @@
 <script>
+  import { resolve } from '$app/paths';
   import { onMount } from 'svelte';
   import { goto } from '$app/navigation';
   import { page } from '$app/stores';
@@ -243,7 +244,7 @@
 </div>
 
 {#if payment}
-  <EditButton href="/{root}/payments/edit/{paymentId}" />
+  <EditButton href={resolve('/[cospendRoot=cospendRoot]/payments/edit/[id]', { cospendRoot: root, id: paymentId })} />
 {/if}
 
 <style>