fix(opencode): declare forceStream on transport for free-tier SSE aggregation

Declares forceStream: true so chatCore properly converts upstream
forced-stream responses to JSON for non-streaming callers.

Co-authored-by: anojndr <anojndr@gmail.com>
Co-authored-by: TEGAR-SRC <tegararrahman17@gmail.com>
Co-authored-by: yxxrn <yxxrn@users.noreply.github.com>
Co-Authored-By: Claude Code <noreply@anthropic.com>

open-sse/providers/registry/opencode.js

@@ -17,6 +17,7 @@ export default {
     headers: {
       "x-opencode-client": "desktop",
     },
+    forceStream: true,
     noAuth: true,
     quirks: {
       forceAutoToolChoiceModels: ["muse-spark-1.3-contributor-free"],