Fix Freebuff: correct User-Agent, metadata fields, session body, preset aliases

- User-Agent: ai-sdk/openai-compatible/1.0.25/codebuff (matches official SDK)
- metadata: freebuff_instance_id (not codebuff_instance_id) + client_id field
- Session POST: empty body {} (not {model: ...})
- Add Freebuff/FreeBuff preset aliases for backward compat

src/codex-launcher-gui

@@ -400,6 +400,24 @@ PROVIDER_PRESETS = {
             "moonshotai/kimi-k2.6", "minimax/minimax-m2.7",
         ],
     },
+    "Freebuff (Free DeepSeek/Kimi)": {
+        "backend_type": "codebuff",
+        "base_url": "https://www.codebuff.com",
+        "oauth_provider": "codebuff",
+        "models": [
+            "deepseek/deepseek-v4-pro", "deepseek/deepseek-v4-flash",
+            "moonshotai/kimi-k2.6", "minimax/minimax-m2.7",
+        ],
+    },
+    "FreeBuff": {
+        "backend_type": "codebuff",
+        "base_url": "https://www.codebuff.com",
+        "oauth_provider": "codebuff",
+        "models": [
+            "deepseek/deepseek-v4-pro", "deepseek/deepseek-v4-flash",
+            "moonshotai/kimi-k2.6", "minimax/minimax-m2.7",
+        ],
+    },
 }
 
 def safe_name(name):

src/translate-proxy.py

@@ -331,11 +331,11 @@ def _codebuff_get_session(token, model):
             return sc["instance_id"]
     try:
         url = f"{_CODEBUFF_API_URL}/api/v1/freebuff/session"
-        body = json.dumps({"model": model}).encode()
+        body = json.dumps({}).encode()
         req = urllib.request.Request(url, data=body, headers={
             "Content-Type": "application/json",
             "Authorization": f"Bearer {token}",
-            "User-Agent": "codex-launcher/3.10.5",
+            "User-Agent": "ai-sdk/openai-compatible/1.0.25/codebuff",
             "x-codebuff-model": model,
         })
         try:
@@ -383,7 +383,7 @@ def _codebuff_start_run(token, agent_id):
     req = urllib.request.Request(url, data=body, headers={
         "Content-Type": "application/json",
         "Authorization": f"Bearer {token}",
-        "User-Agent": "codex-launcher/3.10.5",
+        "User-Agent": "ai-sdk/openai-compatible/1.0.25/codebuff",
     })
     try:
         resp = urllib.request.urlopen(req, timeout=15)
@@ -416,7 +416,7 @@ def _codebuff_finish_run(token, run_id, status="completed"):
     req = urllib.request.Request(url, data=body, headers={
         "Content-Type": "application/json",
         "Authorization": f"Bearer {token}",
-        "User-Agent": "codex-launcher/3.10.5",
+        "User-Agent": "ai-sdk/openai-compatible/1.0.25/codebuff",
     })
     try:
         urllib.request.urlopen(req, timeout=10)
@@ -5324,9 +5324,10 @@ class Handler(http.server.BaseHTTPRequestHandler):
              metadata = {
                  "run_id": run_id,
                  "cost_mode": "free",
+                 "client_id": secrets.token_hex(7)[:13],
              }
              if instance_id:
-                 metadata["codebuff_instance_id"] = instance_id
+                 metadata["freebuff_instance_id"] = instance_id
 
              chat_body = {
                  "model": model,
@@ -5348,7 +5349,7 @@ class Handler(http.server.BaseHTTPRequestHandler):
              headers = {
                  "Content-Type": "application/json",
                  "Authorization": f"Bearer {token}",
-                 "User-Agent": "codex-launcher/3.10.5",
+                 "User-Agent": "ai-sdk/openai-compatible/1.0.25/codebuff",
                  "x-codebuff-model": model,
              }
              if instance_id:
@@ -5496,9 +5497,9 @@ class Handler(http.server.BaseHTTPRequestHandler):
         instance_id = _codebuff_get_session(token, model)
         messages = _cb_input_to_messages(input_data, instructions)
         _codebuff_hard_disable_reasoning(messages)
-        metadata = {"run_id": run_id, "cost_mode": "free"}
+        metadata = {"run_id": run_id, "cost_mode": "free", "client_id": secrets.token_hex(7)[:13]}
         if instance_id:
-            metadata["codebuff_instance_id"] = instance_id
+            metadata["freebuff_instance_id"] = instance_id
         chat_body = {
             "model": model, "messages": messages, "stream": stream,
             "max_tokens": max(body.get("max_output_tokens", 0), 64000),
@@ -5514,7 +5515,7 @@ class Handler(http.server.BaseHTTPRequestHandler):
         if body.get("tool_choice"):
             chat_body["tool_choice"] = body["tool_choice"]
         target = f"{_CODEBUFF_API_URL}/api/v1/chat/completions"
-        headers = {"Content-Type": "application/json", "Authorization": f"Bearer {token}", "User-Agent": "codex-launcher/3.10.5", "x-codebuff-model": model}
+        headers = {"Content-Type": "application/json", "Authorization": f"Bearer {token}", "User-Agent": "ai-sdk/openai-compatible/1.0.25/codebuff", "x-codebuff-model": model}
         if instance_id:
             headers["x-codebuff-instance-id"] = instance_id
         print(f"[codebuff] retry POST {target} model={model} stream={stream} run={run_id} (thinking disabled via DeepSeek native)", file=sys.stderr)