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/lib/api/client.test.ts

@@ -83,7 +83,7 @@ describe('api.get/post/del', () => {
 describe('apiFetch 401 interceptor', () => {
   test('401 response triggers auth.logout({silent:true}) and still throws', async () => {
     const logoutSpy = vi.fn();
-    vi.doMock('$lib/auth/store.svelte', () => ({
+    vi.doMock('#lib/auth/store.svelte.js', () => ({
       logout: logoutSpy,
       login: vi.fn(),
       bootstrap: vi.fn(),
@@ -97,6 +97,6 @@ describe('apiFetch 401 interceptor', () => {
       status: 401
     });
     expect(logoutSpy).toHaveBeenCalledWith({ silent: true });
-    vi.doUnmock('$lib/auth/store.svelte');
+    vi.doUnmock('#lib/auth/store.svelte.js');
   });
 });

web/src/lib/api/client.ts

@@ -44,7 +44,7 @@ export async function apiFetch(path: string, init?: RequestInit): Promise<unknow
       // Lazy import: auth/store imports from this file, so a top-level
       // import would be circular. By the time any 401 actually happens
       // at runtime, both modules have finished loading.
-      const { logout } = await import('$lib/auth/store.svelte');
+      const { logout } = await import('#lib/auth/store.svelte.js');
       await logout({ silent: true });
     }
     // Two error envelope shapes ship in this codebase today: