feat: implement QuestionBank CRUD with pagination and template query

- Add pagination support to findAll (page, limit query params)
- Add findByTemplateId method to service
- Add GET /by-template/:templateId endpoint to controller
- Service already includes CRUD for QuestionBank and QuestionBankItem

server/src/types.ts

@@ -0,0 +1,56 @@
+// server/src/types.ts
+
+export enum ModelType {
+  LLM = 'llm',
+  EMBEDDING = 'embedding',
+  RERANK = 'rerank',
+  VISION = 'vision',
+}
+
+// 1. Model Definition (The "Provider" setup)
+export interface ModelConfig {
+  id: string;
+  name: string; // Display name, e.g. "My DeepSeek"
+  modelId: string; // The actual string ID sent to API, e.g., "deepseek-chat"
+  baseUrl?: string; // Base URL for OpenAI compatible API
+  apiKey?: string; // API key for the service
+  type: ModelType;
+  dimensions?: number;
+  supportsVision?: boolean;
+  maxInputTokens?: number;
+  maxBatchSize?: number;
+  isVectorModel?: boolean;
+  providerName?: string;
+  isEnabled?: boolean;
+  isDefault?: boolean;
+}
+
+// 2. Application Logic Settings (The "App" setup)
+export interface AppSettings {
+  // References to ModelConfig IDs
+  selectedLLMId: string;
+  selectedEmbeddingId: string; // Default for new uploads, and used for query encoding
+  selectedRerankId: string;
+
+  // Model Hyperparameters
+  temperature: number;
+  maxTokens: number;
+
+  // Retrieval
+  enableRerank: boolean;
+  topK: number;
+  similarityThreshold: number;
+  rerankSimilarityThreshold: number;
+  enableFullTextSearch: boolean;
+  hybridVectorWeight: number;
+
+  // Search Enhancement
+  enableQueryExpansion: boolean;
+  enableHyDE: boolean;
+
+  chunkSize: number;
+  chunkOverlap: number;
+
+  // Language
+  language: string;
+}