refactor(open-sse): D1c — forceStream hardcode → PROVIDERS schema (#5)

chatCore providerRequiresStreaming: switch provider-name →
PROVIDERS[provider].forceStream. Thêm forceStream:true vào registry
openai/codex/commandcode. verify-providers allowlist added-fields
(forceStream/urlSuffix verified bằng golden + runtime test riêng).

Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/providers/registry/codex.js

@@ -6,6 +6,7 @@ export default {
   transport: {
     baseUrl: "https://chatgpt.com/backend-api/codex/responses",
     format: "openai-responses",
+    forceStream: true,
     headers: {
       "originator": "codex_cli_rs",
       "User-Agent": "codex_cli_rs/0.136.0"

open-sse/providers/registry/commandcode.js

@@ -4,6 +4,7 @@ export default {
   "transport": {
     "baseUrl": "https://api.commandcode.ai/alpha/generate",
     "format": "commandcode",
+    "forceStream": true,
     "headers": {
       "x-command-code-version": "0.25.7",
       "x-cli-environment": "cli"

open-sse/providers/registry/openai.js

@@ -2,7 +2,8 @@ export default {
   "id": "openai",
   "alias": "openai",
   "transport": {
-    "baseUrl": "https://api.openai.com/v1/chat/completions"
+    "baseUrl": "https://api.openai.com/v1/chat/completions",
+    "forceStream": true
   },
   "models": [
     {