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>

.gitea/workflows/release.yml

@@ -295,12 +295,13 @@ jobs:
       - name: Install deps
         run: npm ci
 
-      # What ships to browsers: `dependencies` and the runtime they pull in
-      # (svelte, devalue). Build and test tooling (vite, vitest, tailwind,
-      # kit's dev server) is left out because none of it reaches a user, and
-      # its open advisories need major-version upgrades tracked separately.
-      - name: npm audit (shipped dependencies)
-        run: npm audit --omit=dev --audit-level=moderate
+      # The whole tree, build and test tooling included. Until #5021 this
+      # audited only what ships to browsers (`--omit=dev`), because vite,
+      # vitest, tailwind and kit carried advisories that needed major
+      # upgrades. Those upgrades landed and the full tree audits clean, so
+      # the tooling that builds the shipped bundle is held to the same bar.
+      - name: npm audit (all dependencies)
+        run: npm audit --audit-level=moderate
 
       - name: Type-check + svelte-check
         run: npm run check