docs: clarify Bun's default registry resolution in index.ts (#1438)

packages/opencode/src/bun/index.ts

@@ -73,6 +73,7 @@ export namespace BunProc {
     // Let Bun handle registry resolution:
     // - If .npmrc files exist, Bun will use them automatically
     // - If no .npmrc files exist, Bun will default to https://registry.npmjs.org
+    // - No need to pass --registry flag
     log.info("installing package using Bun's default registry resolution", { pkg, version })
 
     await BunProc.run(args, {