feat: 新增 gemini-3.1-pro-high/low 模型支持

- 后端默认映射新增 gemini-3.1-pro-high、gemini-3.1-pro-low、gemini-3.1-pro-preview
- 前端模型列表新增 gemini-3.1 系列
- 数据库迁移全量覆写 model_mapping

backend/internal/domain/constants.go

@@ -96,6 +96,11 @@ var DefaultAntigravityModelMapping = map[string]string{
 	"gemini-3-flash-preview":     "gemini-3-flash",
 	"gemini-3-pro-preview":       "gemini-3-pro-high",
 	"gemini-3-pro-image-preview": "gemini-3-pro-image",
+	// Gemini 3.1 白名单
+	"gemini-3.1-pro-high": "gemini-3.1-pro-high",
+	"gemini-3.1-pro-low":  "gemini-3.1-pro-low",
+	// Gemini 3.1 preview 映射
+	"gemini-3.1-pro-preview": "gemini-3.1-pro-high",
 	// 其他官方模型
 	"gpt-oss-120b-medium":    "gpt-oss-120b-medium",
 	"tab_flash_lite_preview": "tab_flash_lite_preview",

backend/migrations/057_add_gemini31_pro_to_model_mapping.sql

@@ -0,0 +1,45 @@
+-- Add gemini-3.1-pro-high, gemini-3.1-pro-low, gemini-3.1-pro-preview to model_mapping
+--
+-- Background:
+-- Antigravity now supports gemini-3.1-pro-high and gemini-3.1-pro-low
+--
+-- Strategy:
+-- Directly overwrite the entire model_mapping with updated mappings
+-- This ensures consistency with DefaultAntigravityModelMapping in constants.go
+
+UPDATE accounts
+SET credentials = jsonb_set(
+    credentials,
+    '{model_mapping}',
+    '{
+        "claude-opus-4-6-thinking": "claude-opus-4-6-thinking",
+        "claude-opus-4-6": "claude-opus-4-6-thinking",
+        "claude-opus-4-5-thinking": "claude-opus-4-6-thinking",
+        "claude-opus-4-5-20251101": "claude-opus-4-6-thinking",
+        "claude-sonnet-4-6": "claude-sonnet-4-6",
+        "claude-sonnet-4-5": "claude-sonnet-4-5",
+        "claude-sonnet-4-5-thinking": "claude-sonnet-4-5-thinking",
+        "claude-sonnet-4-5-20250929": "claude-sonnet-4-5",
+        "claude-haiku-4-5": "claude-sonnet-4-5",
+        "claude-haiku-4-5-20251001": "claude-sonnet-4-5",
+        "gemini-2.5-flash": "gemini-2.5-flash",
+        "gemini-2.5-flash-lite": "gemini-2.5-flash-lite",
+        "gemini-2.5-flash-thinking": "gemini-2.5-flash-thinking",
+        "gemini-2.5-pro": "gemini-2.5-pro",
+        "gemini-3-flash": "gemini-3-flash",
+        "gemini-3-pro-high": "gemini-3-pro-high",
+        "gemini-3-pro-low": "gemini-3-pro-low",
+        "gemini-3-pro-image": "gemini-3-pro-image",
+        "gemini-3-flash-preview": "gemini-3-flash",
+        "gemini-3-pro-preview": "gemini-3-pro-high",
+        "gemini-3-pro-image-preview": "gemini-3-pro-image",
+        "gemini-3.1-pro-high": "gemini-3.1-pro-high",
+        "gemini-3.1-pro-low": "gemini-3.1-pro-low",
+        "gemini-3.1-pro-preview": "gemini-3.1-pro-high",
+        "gpt-oss-120b-medium": "gpt-oss-120b-medium",
+        "tab_flash_lite_preview": "tab_flash_lite_preview"
+    }'::jsonb
+)
+WHERE platform = 'antigravity'
+  AND deleted_at IS NULL
+  AND credentials->'model_mapping' IS NOT NULL;

frontend/src/composables/useModelWhitelist.ts

@@ -73,6 +73,9 @@ const antigravityModels = [
   'gemini-3-pro-high',
   'gemini-3-pro-low',
   'gemini-3-pro-image',
+  // Gemini 3.1 系列
+  'gemini-3.1-pro-high',
+  'gemini-3.1-pro-low',
   // 其他
   'gpt-oss-120b-medium',
   'tab_flash_lite_preview'