feat: OAuth 导入导出、提供商筛选、Gemini 图像生成支持与流式处理增强

- OAuth: 支持通过 Refresh Token 导入账号（文件拖拽/粘贴），OAuth Key 可导出为 JSON
- OAuth: 所有 OAuth 端点添加 require_admin 鉴权
- 提供商管理: 新增状态/API格式/模型三级筛选，后端返回 global_model_ids
- Gemini: 新增图像生成模型适配（finalize_provider_request 钩子 + envelope 跳过不兼容字段）
- 流式处理: buffer 残留数据 flush 与 token 兜底估算
- 上游元数据: 提取 merge_upstream_metadata，配额耗尽模型保留与深度合并
- Antigravity 配额: 无 quotaInfo 时视为耗尽，移除 Other 兜底分组
- README: 新增升级备份与回滚指南

src/services/model/fetch_scheduler.py

@@ -30,6 +30,7 @@ from src.models.database import Provider, ProviderAPIKey
 from src.services.model.upstream_fetcher import (
     UpstreamModelsFetchContext,
     fetch_models_for_key,
+    merge_upstream_metadata,
 )
 from src.services.provider.oauth_token import resolve_oauth_access_token
 from src.services.system.scheduler import get_scheduler
@@ -491,13 +492,9 @@ class ModelFetchScheduler:
 
             # 最佳努力：保存上游元数据（如 Antigravity 配额信息）
             if upstream_metadata and isinstance(upstream_metadata, dict):
-                # NOTE: upstream_metadata is a plain JSON column (not MutableDict),
-                # so in-place mutation won't be persisted reliably. Always assign
-                # a new dict object to mark the column as dirty.
-                current = key.upstream_metadata
-                merged: dict[str, Any] = dict(current) if isinstance(current, dict) else {}
-                merged.update(upstream_metadata)
-                key.upstream_metadata = merged
+                key.upstream_metadata = merge_upstream_metadata(
+                    key.upstream_metadata, upstream_metadata
+                )
 
             # 去重获取模型 ID 列表
             fetched_model_ids: set[str] = set()

src/services/model/upstream_fetcher.py

@@ -82,6 +82,50 @@ async def fetch_models_for_key(
     return await fetcher(ctx, timeout_seconds)
 
 
+def merge_upstream_metadata(
+    current: dict[str, Any] | None,
+    incoming: dict[str, Any],
+) -> dict[str, Any]:
+    """合并上游元数据，对 quota_by_model 做模型级深度合并。
+
+    上游 API 在配额耗尽后可能不再返回该模型的 quotaInfo，因此需要：
+    1. 保留旧数据中已有的 reset_time（当新数据缺少时）
+    2. 保留旧数据中存在但新数据中缺失的模型条目（标记为 100% 已用）
+    """
+    merged: dict[str, Any] = dict(current) if isinstance(current, dict) else {}
+    for ns_key, ns_val in incoming.items():
+        old_ns = merged.get(ns_key)
+        if (
+            isinstance(ns_val, dict)
+            and isinstance(old_ns, dict)
+            and "quota_by_model" in ns_val
+            and "quota_by_model" in old_ns
+        ):
+            old_qbm = old_ns["quota_by_model"]
+            new_qbm = ns_val["quota_by_model"]
+            if isinstance(old_qbm, dict) and isinstance(new_qbm, dict):
+                # 保留新数据中已有模型的旧 reset_time
+                for model_id, new_info in new_qbm.items():
+                    if not isinstance(new_info, dict):
+                        continue
+                    old_info = old_qbm.get(model_id)
+                    if (
+                        isinstance(old_info, dict)
+                        and "reset_time" in old_info
+                        and "reset_time" not in new_info
+                    ):
+                        new_info["reset_time"] = old_info["reset_time"]
+                # 保留新数据中缺失但旧数据中存在的模型（配额耗尽后上游可能不返回）
+                for model_id, old_info in old_qbm.items():
+                    if model_id not in new_qbm and isinstance(old_info, dict):
+                        exhausted = dict(old_info)
+                        exhausted["remaining_fraction"] = 0.0
+                        exhausted["used_percent"] = 100.0
+                        new_qbm[model_id] = exhausted
+        merged[ns_key] = ns_val
+    return merged
+
+
 # Provider-specific fetchers are registered by plugin.register_all()
 # (called from envelope.py bootstrap)
 

src/services/provider/adapters/antigravity/envelope.py

@@ -345,31 +345,45 @@ def wrap_v1internal_request(
     1. 移除 model（移到顶层）
     2. 移除 safetySettings（v1internal 不支持）
     3. 深度清理 [undefined] 字符串
-    4. Claude model tool ID 注入
-    5. Thinking budget 处理（自动注入 + Auto Cap）
-    6. 工具声明清洗（schema 清理 + 字段重命名）
-    7. System Instruction 注入
+    4. Claude model tool ID 注入（图像生成模型跳过）
+    5. Thinking budget 处理
+    6. 工具声明清洗（图像生成模型跳过）
+    7. System Instruction 注入（图像生成模型跳过）
     8. 注入 sessionId（对齐 CLIProxyAPI）
     9. 构建 v1internal 信封
     """
+    from src.api.handlers.gemini.image_gen import is_image_gen_model
+
     inner_request = dict(gemini_request)
     inner_request.pop("model", None)
     inner_request.pop("safetySettings", None)
 
+    is_image_gen = is_image_gen_model(model)
+
     # 1. 深度清理 [undefined]
     _deep_clean_undefined(inner_request)
 
-    # 2. Claude tool ID 注入
-    _inject_claude_tool_ids_request(inner_request, model)
+    if not is_image_gen:
+        # 2. Claude tool ID 注入
+        _inject_claude_tool_ids_request(inner_request, model)
 
     # 3. Thinking budget 处理
     _process_thinking_budget(inner_request, model)
 
-    # 4. 工具声明清洗
-    _clean_tool_declarations(inner_request)
+    if not is_image_gen:
+        # 4. 工具声明清洗
+        _clean_tool_declarations(inner_request)
 
-    # 5. System Instruction 注入
-    _inject_system_instruction(inner_request)
+        # 5. System Instruction 注入
+        _inject_system_instruction(inner_request)
+    else:
+        # 图像生成模型：对齐 AM wrapper.rs，移除不兼容字段
+        inner_request.pop("tools", None)
+        inner_request.pop("toolConfig", None)
+        inner_request.pop("tool_config", None)
+        inner_request.pop("systemInstruction", None)
+        inner_request.pop("system_instruction", None)
+        request_type = "image_gen"
 
     # 6. 注入 sessionId（对齐 CLIProxyAPI/sub2api）
     if "sessionId" not in inner_request:

src/services/provider/adapters/antigravity/plugin.py

@@ -255,6 +255,11 @@ async def fetch_models_antigravity(
 
         quota_info = model_data.get("quotaInfo")
         if not isinstance(quota_info, dict):
+            # 没有 quotaInfo 视为配额耗尽
+            quota_by_model[model_id] = {
+                "remaining_fraction": 0.0,
+                "used_percent": 100.0,
+            }
             continue
 
         remaining = quota_info.get("remainingFraction")
@@ -268,6 +273,14 @@ async def fetch_models_antigravity(
             remaining_fraction = None
 
         if remaining_fraction is None:
+            # remainingFraction 缺失视为配额耗尽
+            payload: dict[str, Any] = {
+                "remaining_fraction": 0.0,
+                "used_percent": 100.0,
+            }
+            if isinstance(reset_time, str) and reset_time.strip():
+                payload["reset_time"] = reset_time.strip()
+            quota_by_model[model_id] = payload
             continue
 
         used_percent = (1.0 - remaining_fraction) * 100.0