fix: mark React output imports as external at tsup level to prevent build errors

- Add function matcher to external array for React output imports
- Fixes 'Could not resolve' errors during React build
- tsup checks external array during its own resolution phase (before esbuild)
- Plugin approach was too late - tsup resolves imports before esbuild plugins run
- React outputs are now marked external early enough to prevent resolution failures

This fixes the issue where tsup tried to resolve React output imports
from files outside the React directory (e.g., cortexideSettingsPane.ts)
before those output files existed.

Author: Tajudeen

src/vs/workbench/contrib/cortexide/browser/react/tsup.config.js

@@ -63,10 +63,21 @@ export default defineConfig({
 	injectStyle: true, // bundle css into the output file
 	outExtension: () => ({ js: '.js' }),
 	treeshake: true,
-	// Mark Node.js built-ins as external
-	// React output imports are handled by the externalReactOutputsPlugin to prevent DTS generation errors
+	// Mark Node.js built-ins and React output imports as external
+	// React outputs MUST be in the external array (not just plugin) because:
+	// 1. tsup does its own import resolution BEFORE esbuild
+	// 2. When tsup encounters imports from files outside React dir (e.g., cortexideSettingsPane.ts),
+	//    it tries to resolve them during tsup's resolution phase
+	// 3. The external array is checked during tsup's phase, plugins only run during esbuild phase
+	// 4. If not in external array, tsup tries to resolve files that don't exist yet → fails
 	external: [
 		'url', 'module', 'fs', 'path', 'os', 'crypto', 'stream', 'util', 'events', 'buffer', 'process',
+		// React output imports - must be external at tsup level to prevent resolution errors
+		// Using function to match both ./react/out/ and ../react/out/ patterns
+		// tsup checks this during its own resolution phase (before esbuild)
+		(id) => {
+			return id.startsWith('./react/out/') || id.startsWith('../react/out/')
+		},
 	],
 	// Use tsconfig.json which has ignoreDeprecations: "6.0" to suppress baseUrl deprecation warnings
 	tsconfig: './tsconfig.json',