feat: add missing service contract interfaces for all CoreServiceName services

Add 11 new contract interfaces with co-located tests:
- IMetadataService (metadata)
- IAuthService (auth)
- IAutomationService (automation)
- IGraphQLService (graphql)
- IAnalyticsService (analytics)
- IRealtimeService (realtime)
- IJobService (job)
- IAIService (ai)
- II18nService (i18n)
- IUIService (ui)
- IWorkflowService (workflow)

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

packages/spec/src/contracts/ai-service.test.ts

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+import { describe, it, expect } from 'vitest';
+import type { IAIService, AIMessage, AIResult } from './ai-service';
+
+describe('AI Service Contract', () => {
+  it('should allow a minimal IAIService implementation with required methods', () => {
+    const service: IAIService = {
+      chat: async (_messages, _options?) => ({ content: '' }),
+      complete: async (_prompt, _options?) => ({ content: '' }),
+    };
+
+    expect(typeof service.chat).toBe('function');
+    expect(typeof service.complete).toBe('function');
+  });
+
+  it('should allow a full implementation with optional methods', () => {
+    const service: IAIService = {
+      chat: async () => ({ content: '' }),
+      complete: async () => ({ content: '' }),
+      embed: async () => [[]],
+      listModels: async () => [],
+    };
+
+    expect(service.embed).toBeDefined();
+    expect(service.listModels).toBeDefined();
+  });
+
+  it('should generate a chat completion', async () => {
+    const service: IAIService = {
+      chat: async (messages): Promise<AIResult> => {
+        const lastMessage = messages[messages.length - 1];
+        return {
+          content: `Echo: ${lastMessage.content}`,
+          model: 'test-model',
+          usage: { promptTokens: 10, completionTokens: 5, totalTokens: 15 },
+        };
+      },
+      complete: async () => ({ content: '' }),
+    };
+
+    const messages: AIMessage[] = [
+      { role: 'system', content: 'You are a helpful assistant.' },
+      { role: 'user', content: 'Hello' },
+    ];
+
+    const result = await service.chat(messages);
+    expect(result.content).toBe('Echo: Hello');
+    expect(result.model).toBe('test-model');
+    expect(result.usage?.totalTokens).toBe(15);
+  });
+
+  it('should generate a text completion', async () => {
+    const service: IAIService = {
+      chat: async () => ({ content: '' }),
+      complete: async (prompt, options?): Promise<AIResult> => ({
+        content: `Completed: ${prompt}`,
+        model: options?.model ?? 'default',
+      }),
+    };
+
+    const result = await service.complete('The sky is', { model: 'gpt-4', maxTokens: 50 });
+    expect(result.content).toContain('The sky is');
+    expect(result.model).toBe('gpt-4');
+  });
+
+  it('should generate embeddings', async () => {
+    const service: IAIService = {
+      chat: async () => ({ content: '' }),
+      complete: async () => ({ content: '' }),
+      embed: async (input) => {
+        const texts = Array.isArray(input) ? input : [input];
+        return texts.map(() => [0.1, 0.2, 0.3]);
+      },
+    };
+
+    const embeddings = await service.embed!('Hello world');
+    expect(embeddings).toHaveLength(1);
+    expect(embeddings[0]).toEqual([0.1, 0.2, 0.3]);
+
+    const batch = await service.embed!(['Hello', 'World']);
+    expect(batch).toHaveLength(2);
+  });
+
+  it('should list available models', async () => {
+    const service: IAIService = {
+      chat: async () => ({ content: '' }),
+      complete: async () => ({ content: '' }),
+      listModels: async () => ['gpt-4', 'gpt-3.5-turbo', 'claude-3-sonnet'],
+    };
+
+    const models = await service.listModels!();
+    expect(models).toHaveLength(3);
+    expect(models).toContain('gpt-4');
+  });
+});

packages/spec/src/contracts/ai-service.ts

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+// Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * IAIService - AI Engine Service Contract
+ *
+ * Defines the interface for AI capabilities (NLQ, chat, suggestions, embeddings)
+ * in ObjectStack. Concrete implementations (OpenAI, Anthropic, Ollama, etc.)
+ * should implement this interface.
+ *
+ * Follows Dependency Inversion Principle - plugins depend on this interface,
+ * not on concrete AI/LLM provider implementations.
+ *
+ * Aligned with CoreServiceName 'ai' in core-services.zod.ts.
+ */
+
+/**
+ * A chat message in a conversation
+ */
+export interface AIMessage {
+    /** Message role */
+    role: 'system' | 'user' | 'assistant';
+    /** Message content */
+    content: string;
+}
+
+/**
+ * Options for AI completion/chat requests
+ */
+export interface AIRequestOptions {
+    /** Model identifier to use */
+    model?: string;
+    /** Sampling temperature (0-2) */
+    temperature?: number;
+    /** Maximum tokens to generate */
+    maxTokens?: number;
+    /** Stop sequences */
+    stop?: string[];
+}
+
+/**
+ * Result of an AI completion/chat request
+ */
+export interface AIResult {
+    /** Generated text content */
+    content: string;
+    /** Model used for generation */
+    model?: string;
+    /** Token usage statistics */
+    usage?: {
+        promptTokens: number;
+        completionTokens: number;
+        totalTokens: number;
+    };
+}
+
+export interface IAIService {
+    /**
+     * Generate a chat completion from a conversation
+     * @param messages - Array of conversation messages
+     * @param options - Optional request configuration
+     * @returns AI-generated response
+     */
+    chat(messages: AIMessage[], options?: AIRequestOptions): Promise<AIResult>;
+
+    /**
+     * Generate a text completion from a prompt
+     * @param prompt - Input prompt string
+     * @param options - Optional request configuration
+     * @returns AI-generated response
+     */
+    complete(prompt: string, options?: AIRequestOptions): Promise<AIResult>;
+
+    /**
+     * Generate embeddings for a text input
+     * @param input - Text or array of texts to embed
+     * @param model - Optional embedding model identifier
+     * @returns Array of embedding vectors
+     */
+    embed?(input: string | string[], model?: string): Promise<number[][]>;
+
+    /**
+     * List available models
+     * @returns Array of model identifiers
+     */
+    listModels?(): Promise<string[]>;
+}

packages/spec/src/contracts/analytics-service.test.ts

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+import { describe, it, expect } from 'vitest';
+import type { IAnalyticsService, AnalyticsResult, CubeMeta } from './analytics-service';
+
+describe('Analytics Service Contract', () => {
+  it('should allow a minimal IAnalyticsService implementation with required methods', () => {
+    const service: IAnalyticsService = {
+      query: async (_query) => ({ rows: [], fields: [] }),
+      getMeta: async () => [],
+    };
+
+    expect(typeof service.query).toBe('function');
+    expect(typeof service.getMeta).toBe('function');
+  });
+
+  it('should allow a full implementation with optional methods', () => {
+    const service: IAnalyticsService = {
+      query: async () => ({ rows: [], fields: [] }),
+      getMeta: async () => [],
+      generateSql: async () => ({ sql: 'SELECT 1', params: [] }),
+    };
+
+    expect(service.generateSql).toBeDefined();
+  });
+
+  it('should execute an analytics query', async () => {
+    const service: IAnalyticsService = {
+      query: async (query): Promise<AnalyticsResult> => ({
+        rows: [
+          { 'orders.status': 'active', 'orders.count': 42 },
+          { 'orders.status': 'closed', 'orders.count': 18 },
+        ],
+        fields: [
+          { name: 'orders.status', type: 'string' },
+          { name: 'orders.count', type: 'number' },
+        ],
+      }),
+      getMeta: async () => [],
+    };
+
+    const result = await service.query({
+      cube: 'orders',
+      measures: ['orders.count'],
+      dimensions: ['orders.status'],
+    });
+
+    expect(result.rows).toHaveLength(2);
+    expect(result.fields).toHaveLength(2);
+    expect(result.rows[0]['orders.count']).toBe(42);
+  });
+
+  it('should return cube metadata', async () => {
+    const cubes: CubeMeta[] = [{
+      name: 'orders',
+      title: 'Orders',
+      measures: [{ name: 'orders.count', type: 'count' }],
+      dimensions: [{ name: 'orders.status', type: 'string' }],
+    }];
+
+    const service: IAnalyticsService = {
+      query: async () => ({ rows: [], fields: [] }),
+      getMeta: async (cubeName?) => {
+        if (cubeName) return cubes.filter(c => c.name === cubeName);
+        return cubes;
+      },
+    };
+
+    const meta = await service.getMeta();
+    expect(meta).toHaveLength(1);
+    expect(meta[0].name).toBe('orders');
+    expect(meta[0].measures).toHaveLength(1);
+  });
+
+  it('should generate SQL without executing', async () => {
+    const service: IAnalyticsService = {
+      query: async () => ({ rows: [], fields: [] }),
+      getMeta: async () => [],
+      generateSql: async (query) => ({
+        sql: `SELECT COUNT(*) FROM ${query.cube}`,
+        params: [],
+      }),
+    };
+
+    const result = await service.generateSql!({
+      cube: 'orders',
+      measures: ['orders.count'],
+    });
+
+    expect(result.sql).toContain('orders');
+    expect(result.params).toEqual([]);
+  });
+});

packages/spec/src/contracts/analytics-service.ts

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+// Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * IAnalyticsService - Analytics / BI Service Contract
+ *
+ * Defines the interface for analytical query execution and semantic layer
+ * metadata discovery in ObjectStack. Concrete implementations (Cube.js, custom, etc.)
+ * should implement this interface.
+ *
+ * Follows Dependency Inversion Principle - plugins depend on this interface,
+ * not on concrete analytics engine implementations.
+ *
+ * Aligned with CoreServiceName 'analytics' in core-services.zod.ts.
+ */
+
+/**
+ * An analytical query definition
+ */
+export interface AnalyticsQuery {
+    /** Target cube name */
+    cube: string;
+    /** Measures to compute (e.g. ['orders.count', 'orders.totalRevenue']) */
+    measures?: string[];
+    /** Dimensions to group by (e.g. ['orders.status', 'orders.createdAt']) */
+    dimensions?: string[];
+    /** Filter conditions */
+    filters?: Array<{
+        member: string;
+        operator: string;
+        values?: string[];
+    }>;
+    /** Time dimension configuration */
+    timeDimensions?: Array<{
+        dimension: string;
+        granularity?: string;
+        dateRange?: string | string[];
+    }>;
+    /** Result limit */
+    limit?: number;
+    /** Result offset */
+    offset?: number;
+}
+
+/**
+ * Analytics query result
+ */
+export interface AnalyticsResult {
+    /** Result rows */
+    rows: Record<string, unknown>[];
+    /** Column metadata */
+    fields: Array<{
+        name: string;
+        type: string;
+    }>;
+    /** Generated SQL (if available) */
+    sql?: string;
+}
+
+/**
+ * Cube metadata for discovery
+ */
+export interface CubeMeta {
+    /** Cube name */
+    name: string;
+    /** Human-readable title */
+    title?: string;
+    /** Available measures */
+    measures: Array<{ name: string; type: string; title?: string }>;
+    /** Available dimensions */
+    dimensions: Array<{ name: string; type: string; title?: string }>;
+}
+
+export interface IAnalyticsService {
+    /**
+     * Execute an analytical query
+     * @param query - The analytics query definition
+     * @returns Query results with rows and field metadata
+     */
+    query(query: AnalyticsQuery): Promise<AnalyticsResult>;
+
+    /**
+     * Get available cube metadata for discovery
+     * @param cubeName - Optional cube name to filter (returns all if omitted)
+     * @returns Array of cube metadata definitions
+     */
+    getMeta(cubeName?: string): Promise<CubeMeta[]>;
+
+    /**
+     * Generate SQL for a query without executing it (dry-run)
+     * @param query - The analytics query definition
+     * @returns Generated SQL string and parameters
+     */
+    generateSql?(query: AnalyticsQuery): Promise<{ sql: string; params: unknown[] }>;
+}