fix(ci): build design-system tokens before tsc/vite (Day 4 follow-up)

CI run 455/456 surfaced:
  src/features/player/components/AudioVisualizer.tsx(22,8): error TS2307:
  Cannot find module '@veza/design-system/tokens-generated' or its
  corresponding type declarations.

Root cause: the sprint 2 design-system migration (commits a25ad2e0 →
ab923def) replaced manual src/ exports with Style Dictionary output in
packages/design-system/dist/. That `dist/` is gitignored — by design,
since it's generated artifact — but no step in the CI workflows runs
the generator before tsc/vite/vitest fire.

apps/web imports `@veza/design-system/tokens-generated`, which the
package's `exports` field maps to `./dist/tokens.ts`. With dist/ empty
on a fresh checkout, the import resolves to undefined → TS2307.

Two-pronged fix:

(1) packages/design-system/package.json — add a `prepare` script that
    runs Style Dictionary. npm fires `prepare` after `npm install`
    AND `npm ci`, so any workspace install populates dist/ without an
    extra workflow change. Also covers fresh dev clones.

(2) .github/workflows/{ci.yml,e2e.yml} — explicit
    `npm run build:tokens --workspace=@veza/design-system` step
    immediately after `npm ci`. Belt-and-suspenders against any npm
    version where `prepare` is silent or filtered (lifecycle script
    skipping has burned us before — `--ignore-scripts` flags, etc.).

Verified locally:
  $ rm -rf packages/design-system/dist/
  $ npm run build:tokens --workspace=@veza/design-system
  ✓ Style Dictionary build complete.
  $ cd apps/web && npx tsc --noEmit
  (clean)

SKIP_TESTS=1 — config-only changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -106,6 +106,16 @@ jobs:
             - name: Install dependencies
               run: npm ci
 
+            # Sprint 2 design-system migrated to Style Dictionary; the
+            # generated tokens live in packages/design-system/dist/ which
+            # is gitignored. apps/web imports `@veza/design-system/tokens-generated`,
+            # so dist/ MUST exist before tsc/vitest/build runs.
+            # `prepare` in the package would normally cover npm ci, but
+            # this explicit step makes the dependency loud and runnable
+            # standalone for local debugging.
+            - name: Build design tokens
+              run: npm run build:tokens --workspace=@veza/design-system
+
             # Prevents drift between veza-backend-api/openapi.yaml and
             # apps/web/src/types/generated/. Regenerates then fails if
             # git diff is non-empty.

.github/workflows/e2e.yml

@@ -107,6 +107,14 @@ jobs:
             - name: Install dependencies
               run: npm ci
 
+            # Sprint 2 design-system migrated to Style Dictionary; the
+            # generated tokens live in packages/design-system/dist/
+            # (gitignored). The Playwright-spawned Vite imports them via
+            # `@veza/design-system/tokens-generated`, so dist/ MUST exist
+            # before vite starts.
+            - name: Build design tokens
+              run: npm run build:tokens --workspace=@veza/design-system
+
             # Playwright tests reach the frontend via http://veza.fr:5174,
             # which the browsers resolve via /etc/hosts. Without this entry
             # the navigation step times out.

packages/design-system/package.json

@@ -17,7 +17,8 @@
   ],
   "scripts": {
     "build": "node style-dictionary.config.mjs",
-    "build:tokens": "node style-dictionary.config.mjs"
+    "build:tokens": "node style-dictionary.config.mjs",
+    "prepare": "node style-dictionary.config.mjs"
   },
   "devDependencies": {
     "style-dictionary": "^4.4.0"