chore(deps): SvelteKit 3 with adapter-static 4 and TypeScript 6, full-tree npm audit (#5021)

Merges Renovate's kit 3 (PR #149) and adapter-static 4 (PR #148) bumps,
plus the migration they need. The mechanical part is `sv migrate
sveltekit-3`, run one task at a time and reviewed:

- svelte.config.js is gone. Its options move into sveltekit() in
  vite.config.ts, exported as kitOptions so vitest.config.ts runs the
  same kit setup, including the $test-utils alias the tests import.
- $lib becomes #lib through package.json "imports". There is no
  src/lib/index, so only the "#lib/*" entry is kept.
- tsconfig extends $app/tsconfig.
- Peer floors raised to kit 3's requirements: svelte ^5.57.1, vite
  ^8.0.12, svelte-check ^4.7.5.

By hand, from the codemod's list of non-automated tasks:

- goto's replaceState option is now replace; keepFocus becomes
  reset: false. For the search typeahead, reset: false also stops the
  scroll-to-top, which is wanted while typing.
- The test setup mocks drop pushState/replaceState and $app/paths
  base/assets, which kit 3 removed, and mock refreshAll in place of
  invalidateAll.
- The other flagged files only read page.url or goto internal routes,
  so they needed no change.

TypeScript goes to ^6, not the ^7 Renovate offers: kit 3 declares
typescript ^6 as a peer and svelte-check 4.7 accepts ^5 || ^6. Move to
7 once both accept it.

With Tailwind 4 and kit 3 in, `npm audit` on the whole tree reports 0,
so the web lane now audits every dependency rather than only what
ships to browsers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/routes/page.test.ts

@@ -2,10 +2,10 @@ import { afterEach, beforeEach, describe, expect, test, vi } from 'vitest';
 import { render, screen, within } from '@testing-library/svelte';
 import { readable } from 'svelte/store';
 import { emptyLikesMock } from '../test-utils/mocks/likes';
-import type { Playlist } from '$lib/api/types';
+import type { Playlist } from '#lib/api/types.js';
 
 // Mock all the queries the home page constructs.
-vi.mock('$lib/api/home', () => ({
+vi.mock('#lib/api/home.js', () => ({
   createHomeQuery: () =>
     readable({
       data: {
@@ -23,20 +23,20 @@ vi.mock('$lib/api/home', () => ({
     })
 }));
 
-vi.mock('$lib/api/playlists', () => ({
+vi.mock('#lib/api/playlists.js', () => ({
   createPlaylistsQuery: vi.fn()
 }));
 
-vi.mock('$lib/api/me', () => ({
+vi.mock('#lib/api/me.js', () => ({
   createSystemPlaylistsStatusQuery: vi.fn()
 }));
 
 // LikeButton imports — needed because the home renders cards that may use it.
-vi.mock('$lib/api/likes', () => emptyLikesMock());
+vi.mock('#lib/api/likes.js', () => emptyLikesMock());
 
 import Page from './+page.svelte';
-import { createPlaylistsQuery } from '$lib/api/playlists';
-import { createSystemPlaylistsStatusQuery } from '$lib/api/me';
+import { createPlaylistsQuery } from '#lib/api/playlists.js';
+import { createSystemPlaylistsStatusQuery } from '#lib/api/me.js';
 
 const emptyPlaylistsResponse = { owned: [], public: [] };