Fix CI: build packages before tests, generate stats for Chromatic

- Add build:packages step before test step in CI so build.test.ts
  can import from dist/ (which is gitignored and not available in CI)
- Add --stats-json to storybook build so Chromatic TurboSnap can find
  preview-stats.json

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: xrendan

.github/workflows/ci.yml

@@ -16,6 +16,9 @@ jobs:
             - name: Install dependencies
               run: bun install --frozen-lockfile
 
+            - name: Build packages
+              run: bun run build:packages
+
             - name: Run tests
               run: bun run test
 

package.json

@@ -7,7 +7,7 @@
     "node": ">=22.0"
   },
   "scripts": {
-    "build": "storybook build -o storybook-static",
+    "build": "storybook build -o storybook-static --stats-json",
     "build:packages": "bun run build:colours && bun run build:components && bun run build:charts",
     "build:colours": "cd packages/colours && bun run build",
     "build:components": "cd packages/components && bun run build",