fix(styles): stop scanning every component for utility sources

Component discovery is not utility-source discovery: scanning all
built-in and plugin component directories made Tailwind/Iconify generate
rules for components the app never renders. Packages that need scanning
opt in through styles.source.

Pre-existing working-tree change, committed as-is rather than authored
here.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/cli/src/build.ts

@@ -620,10 +620,14 @@ export async function runBuild(appRoot: string): Promise<void> {
         appDir,
         appRoot: root,
         mode: "production",
-        sources: [
-          ...componentDirs,
-          ...pluginContributions.styles.flatMap((style) => (style.source ? [style.source] : [])),
-        ],
+        // Component discovery is not style discovery. Built-in and plugin
+        // components own their CSS; scanning every available component makes
+        // Tailwind/Iconify generate rules for packages and components the app
+        // never renders. Packages that intentionally use app utilities opt in
+        // through an explicit styles.source contribution.
+        sources: pluginContributions.styles.flatMap((style) =>
+          style.source ? [style.source] : [],
+        ),
         entries: pluginContributions.styles.flatMap((style) => (style.entry ? [style.entry] : [])),
       },
       config.styles,