ci: add build step before tests

Tests need dist folder for circular dependency breaking require() calls.
Code uses require('#packages/operations') which loads from dist in tests.

Example from src/packages/normalize.ts:75:
  require('#packages/operations') // Breaks circular dep

Without dist, these requires fail with 'Cannot find module'.

Author: jdalton

.github/workflows/ci.yml

@@ -99,6 +99,9 @@ jobs:
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
+      - name: Build project
+        run: pnpm run build
+
       - name: Run main tests
         run: pnpm exec vitest --config .config/vitest.config.mts run
 
@@ -126,6 +129,9 @@ jobs:
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
+      - name: Build project
+        run: pnpm run build
+
       - name: Run isolated tests
         run: pnpm exec vitest --config .config/vitest.config.isolated.mts run