fix: exclude worktree directories from vitest test discovery

.worktrees/ and .claude/ contain git worktrees from other developers
which have their own test files. Without exclusion, vitest picks them
up and fails due to mismatched React/module resolution.

vitest.config.ts

@@ -31,6 +31,8 @@ export default defineConfig({
       "**/node_modules/**",
       "**/dist/**",
       "**/.{idea,git,cache,output,temp}/**",
+      ".worktrees/**",
+      ".claude/**",
     ],
     // These env vars are injected into process.env BEFORE test files are
     // imported, ensuring apps/api/src/config.ts picks them up correctly.