feat(admin): LLM config, knowledge base, and WeCom AI binding

Add owner-scoped model API settings, uploadable knowledge bases, and WeCom bot AI/KB wiring with OpenAI-compatible URL normalization.

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

server/dukang-api/prisma/schema.prisma

@@ -352,24 +352,92 @@ model SystemConfig {
 
 /// 企业微信智能机器人（HQ 可创建多实例，长连接）
 model WecomBot {
-  id          BigInt    @id @default(autoincrement()) @db.UnsignedBigInt
-  name        String    @db.VarChar(64)
-  role        String    @db.VarChar(32)
-  botId       String    @unique @map("bot_id") @db.VarChar(128)
-  secret      String    @db.VarChar(256)
-  avatarUrl   String?   @map("avatar_url") @db.VarChar(512)
-  welcome     String?   @db.VarChar(1024)
+  id              BigInt    @id @default(autoincrement()) @db.UnsignedBigInt
+  name            String    @db.VarChar(64)
+  role            String    @db.VarChar(32)
+  botId           String    @unique @map("bot_id") @db.VarChar(128)
+  secret          String    @db.VarChar(256)
+  avatarUrl       String?   @map("avatar_url") @db.VarChar(512)
+  welcome         String?   @db.VarChar(1024)
   /// JSON 字符串数组，如 ["ticket.create","user.view_sms"]
-  permissions String    @db.Text
-  enabled     Boolean   @default(true)
-  sortOrder   Int       @default(0) @map("sort_order")
-  createdAt   DateTime  @default(now()) @map("created_at") @db.DateTime(3)
-  updatedAt   DateTime  @updatedAt @map("updated_at") @db.DateTime(3)
+  permissions     String    @db.Text
+  /// 未匹配指令时是否调用语言模型
+  aiEnabled       Boolean   @default(false) @map("ai_enabled")
+  llmConfigId     BigInt?   @map("llm_config_id") @db.UnsignedBigInt
+  knowledgeBaseId BigInt?   @map("knowledge_base_id") @db.UnsignedBigInt
+  enabled         Boolean   @default(true)
+  sortOrder       Int       @default(0) @map("sort_order")
+  createdAt       DateTime  @default(now()) @map("created_at") @db.DateTime(3)
+  updatedAt       DateTime  @updatedAt @map("updated_at") @db.DateTime(3)
+
+  llmConfig     LlmApiConfig?  @relation(fields: [llmConfigId], references: [id], onDelete: SetNull)
+  knowledgeBase KnowledgeBase? @relation(fields: [knowledgeBaseId], references: [id], onDelete: SetNull)
 
   @@index([enabled, sortOrder])
+  @@index([llmConfigId])
+  @@index([knowledgeBaseId])
   @@map("wecom_bot")
 }
 
+/// HQ 语言模型 API 配置（非超管仅可见/可开关自己创建的）
+model LlmApiConfig {
+  id                   BigInt   @id @default(autoincrement()) @db.UnsignedBigInt
+  name                 String   @db.VarChar(64)
+  provider             String   @db.VarChar(32)
+  baseUrl              String   @map("base_url") @db.VarChar(512)
+  apiKey               String   @map("api_key") @db.VarChar(512)
+  modelName            String   @map("model_name") @db.VarChar(128)
+  temperature          Decimal? @db.Decimal(3, 2)
+  maxTokens            Int?     @map("max_tokens")
+  systemPrompt         String?  @map("system_prompt") @db.Text
+  enabled              Boolean  @default(true)
+  createdByHqAccountId BigInt   @map("created_by_hq_account_id") @db.UnsignedBigInt
+  createdAt            DateTime @default(now()) @map("created_at") @db.DateTime(3)
+  updatedAt            DateTime @updatedAt @map("updated_at") @db.DateTime(3)
+
+  wecomBots WecomBot[]
+
+  @@index([createdByHqAccountId, enabled])
+  @@map("llm_api_config")
+}
+
+/// HQ 知识库
+model KnowledgeBase {
+  id                   BigInt   @id @default(autoincrement()) @db.UnsignedBigInt
+  name                 String   @db.VarChar(128)
+  description          String?  @db.VarChar(512)
+  enabled              Boolean  @default(true)
+  createdByHqAccountId BigInt   @map("created_by_hq_account_id") @db.UnsignedBigInt
+  createdAt            DateTime @default(now()) @map("created_at") @db.DateTime(3)
+  updatedAt            DateTime @updatedAt @map("updated_at") @db.DateTime(3)
+
+  documents KnowledgeDocument[]
+  wecomBots WecomBot[]
+
+  @@index([createdByHqAccountId, enabled])
+  @@map("knowledge_base")
+}
+
+model KnowledgeDocument {
+  id              BigInt   @id @default(autoincrement()) @db.UnsignedBigInt
+  knowledgeBaseId BigInt   @map("knowledge_base_id") @db.UnsignedBigInt
+  title           String   @db.VarChar(256)
+  fileName        String?  @map("file_name") @db.VarChar(256)
+  fileUrl         String?  @map("file_url") @db.VarChar(1024)
+  mimeType        String?  @map("mime_type") @db.VarChar(128)
+  sizeBytes       Int?     @map("size_bytes")
+  contentText     String?  @map("content_text") @db.LongText
+  status          String   @default("READY") @db.VarChar(16)
+  errorMessage    String?  @map("error_message") @db.VarChar(512)
+  createdAt       DateTime @default(now()) @map("created_at") @db.DateTime(3)
+  updatedAt       DateTime @updatedAt @map("updated_at") @db.DateTime(3)
+
+  knowledgeBase KnowledgeBase @relation(fields: [knowledgeBaseId], references: [id], onDelete: Cascade)
+
+  @@index([knowledgeBaseId])
+  @@map("knowledge_document")
+}
+
 model MockSmsCode {
   id        BigInt   @id @default(autoincrement()) @db.UnsignedBigInt
   phone     String   @db.VarChar(20)