修复：移除请求参数 projectId 降级，改为实时获取

根本原因：请求参数中的 projectId 是客户端缓存的，属于之前账户，
导致账户切换后使用错误的 projectId，返回 403 权限错误。

修改内容：
1. 移除对 request.project 的降级依赖
2. 当账户无 projectId 和 tempProjectId 时，实时调用 loadCodeAssist
3. 获取后缓存到 tempProjectId 供后续请求使用
4. 如果仍无法获取，返回 403 配置错误

影响端点：
- /v1internal:generateContent
- /v1internal:streamGenerateContent

src/handlers/geminiHandlers.js

@@ -1104,21 +1104,46 @@ async function handleGenerateContent(req, res) {
 
     const client = await geminiAccountService.getOauthClient(accessToken, refreshToken, proxyConfig)
 
-    // 智能处理项目ID：优先使用配置的 projectId，降级到临时 tempProjectId，最后使用请求参数
+    // 智能处理项目ID：优先使用配置的 projectId，降级到临时 tempProjectId
-    const effectiveProjectId = account.projectId || account.tempProjectId || project || null
+    let effectiveProjectId = account.projectId || account.tempProjectId || null
+
+    // 如果没有任何项目ID，尝试调用 loadCodeAssist 获取
+    if (!effectiveProjectId) {
+      try {
+        logger.info('📋 No projectId available, attempting to fetch from loadCodeAssist...')
+        const loadResponse = await geminiAccountService.loadCodeAssist(client, null, proxyConfig)
+
+        if (loadResponse.cloudaicompanionProject) {
+          effectiveProjectId = loadResponse.cloudaicompanionProject
+          // 保存临时项目ID
+          await geminiAccountService.updateTempProjectId(accountId, effectiveProjectId)
+          logger.info(`📋 Fetched and cached temporary projectId: ${effectiveProjectId}`)
+        }
+      } catch (loadError) {
+        logger.warn('Failed to fetch projectId from loadCodeAssist:', loadError.message)
+      }
+    }
+
+    // 如果还是没有项目ID，返回错误
+    if (!effectiveProjectId) {
+      return res.status(403).json({
+        error: {
+          message:
+            'This account requires a project ID to be configured. Please configure a project ID in the account settings.',
+          type: 'configuration_required'
+        }
+      })
+    }
 
     logger.info('📋 项目ID处理逻辑', {
       accountProjectId: account.projectId,
       accountTempProjectId: account.tempProjectId,
-      requestProjectId: project,
       effectiveProjectId,
       decision: account.projectId
         ? '使用账户配置'
         : account.tempProjectId
           ? '使用临时项目ID'
-          : project
+          : '从loadCodeAssist获取'
-            ? '使用请求参数'
-            : '不使用项目ID'
     })
 
     const response = await geminiAccountService.generateContent(
@@ -1291,21 +1316,46 @@ async function handleStreamGenerateContent(req, res) {
 
     const client = await geminiAccountService.getOauthClient(accessToken, refreshToken, proxyConfig)
 
-    // 智能处理项目ID：优先使用配置的 projectId，降级到临时 tempProjectId，最后使用请求参数
+    // 智能处理项目ID：优先使用配置的 projectId，降级到临时 tempProjectId
-    const effectiveProjectId = account.projectId || account.tempProjectId || project || null
+    let effectiveProjectId = account.projectId || account.tempProjectId || null
+
+    // 如果没有任何项目ID，尝试调用 loadCodeAssist 获取
+    if (!effectiveProjectId) {
+      try {
+        logger.info('📋 No projectId available, attempting to fetch from loadCodeAssist...')
+        const loadResponse = await geminiAccountService.loadCodeAssist(client, null, proxyConfig)
+
+        if (loadResponse.cloudaicompanionProject) {
+          effectiveProjectId = loadResponse.cloudaicompanionProject
+          // 保存临时项目ID
+          await geminiAccountService.updateTempProjectId(accountId, effectiveProjectId)
+          logger.info(`📋 Fetched and cached temporary projectId: ${effectiveProjectId}`)
+        }
+      } catch (loadError) {
+        logger.warn('Failed to fetch projectId from loadCodeAssist:', loadError.message)
+      }
+    }
+
+    // 如果还是没有项目ID，返回错误
+    if (!effectiveProjectId) {
+      return res.status(403).json({
+        error: {
+          message:
+            'This account requires a project ID to be configured. Please configure a project ID in the account settings.',
+          type: 'configuration_required'
+        }
+      })
+    }
 
     logger.info('📋 流式请求项目ID处理逻辑', {
       accountProjectId: account.projectId,
       accountTempProjectId: account.tempProjectId,
-      requestProjectId: project,
       effectiveProjectId,
       decision: account.projectId
         ? '使用账户配置'
         : account.tempProjectId
           ? '使用临时项目ID'
-          : project
+          : '从loadCodeAssist获取'
-            ? '使用请求参数'
-            : '不使用项目ID'
     })
 
     const streamResponse = await geminiAccountService.generateContentStream(