feat(mcp): MCP Server Core + Adapter Framework

Implement the foundation of the MCP server with a robust,
extensible adapter framework. This establishes the core protocol
handler and plugin system for all future adapters.

Implementation:
- JSON-RPC 2.0 protocol handler with full spec compliance
- Message routing and request/response handling
- Structured error handling with proper error codes
- Server lifecycle management (start, stop, health checks)
- Stdio transport for process communication
- Abstract Transport interface for future HTTP support
- Base adapter interfaces (Adapter, ToolAdapter)
- Adapter lifecycle hooks (initialize, shutdown, healthCheck)
- Adapter Registry for management and execution routing
- Message handler utilities and logger
- Extracted pure functions following testability guidelines

Features:
✅ JSON-RPC 2.0 protocol implementation
✅ Stdio transport with event-based communication
✅ Extensible adapter framework with plugin architecture
✅ Dynamic adapter registration/unregistration
✅ Structured error handling throughout
✅ Comprehensive README with architecture docs
✅ Kebab-case file naming for consistency

Testing:
- 80 tests, all passing
- 67% statement coverage (utils at 94%+, integration at >60%)
- Unit tests for JSON-RPC protocol (23 tests)
- Unit tests for message handlers (25 tests)
- Unit tests for adapter registry (23 tests)
- Integration tests for full server stack (9 tests)
- Mock adapter for testing framework

Documentation:
- Comprehensive README with examples
- Architecture overview with diagrams
- API reference for all public classes
- Quick start guide with configuration examples

Branch: feat/mcp-server-core
Priority: High (blocks all other Epic #3 issues)
Estimate: 3 days (actual: ~6 hours with AI assistance)
Parent Epic: #26 (Epic: MCP Integration)

Issue: #27

Author: prosdev

packages/mcp-server/README.md

@@ -4,7 +4,7 @@
  */
 
 import { ErrorCode } from '../server/protocol/types';
-import type { ToolAdapter } from './ToolAdapter';
+import type { ToolAdapter } from './tool-adapter';
 import type { AdapterContext, ToolDefinition, ToolExecutionContext, ToolResult } from './types';
 
 export interface RegistryConfig {

…p-server/src/adapters/AdapterRegistry.ts …-server/src/adapters/adapter-registry.tspackages/mcp-server/src/adapters/AdapterRegistry.ts renamed to packages/mcp-server/src/adapters/adapter-registry.ts packages/mcp-server/src/adapters/AdapterRegistry.ts renamed to packages/mcp-server/src/adapters/adapter-registry.ts

@@ -3,7 +3,7 @@
  * Extends Adapter to provide tool-specific functionality
  */
 
-import { Adapter } from './Adapter';
+import { Adapter } from './adapter';
 import type { ToolDefinition, ToolExecutionContext, ToolResult, ValidationResult } from './types';
 
 export abstract class ToolAdapter extends Adapter {

…kages/mcp-server/src/adapters/Adapter.ts …kages/mcp-server/src/adapters/adapter.tspackages/mcp-server/src/adapters/Adapter.ts renamed to packages/mcp-server/src/adapters/adapter.ts packages/mcp-server/src/adapters/Adapter.ts renamed to packages/mcp-server/src/adapters/adapter.ts

@@ -4,22 +4,22 @@
  */
 
 // Adapter exports
-export { Adapter } from './adapters/Adapter';
-export { AdapterRegistry, type RegistryConfig } from './adapters/AdapterRegistry';
-export { ToolAdapter } from './adapters/ToolAdapter';
+export { Adapter } from './adapters/adapter';
+export { AdapterRegistry, type RegistryConfig } from './adapters/adapter-registry';
+export { ToolAdapter } from './adapters/tool-adapter';
 export * from './adapters/types';
 // Core exports
-export { MCPServer, type MCPServerConfig } from './server/MCPServer';
+export { MCPServer, type MCPServerConfig } from './server/mcp-server';
 // Protocol exports
 export { JSONRPCHandler } from './server/protocol/jsonrpc';
 export * from './server/protocol/types';
-export { StdioTransport } from './server/transport/StdioTransport';
+export { StdioTransport } from './server/transport/stdio-transport';
 // Transport exports
 export {
   Transport,
   type TransportConfig,
   type TransportMessage,
-} from './server/transport/Transport';
+} from './server/transport/transport';
 
 // Utility exports
 export { ConsoleLogger } from './utils/logger';

…s/mcp-server/src/adapters/ToolAdapter.ts …/mcp-server/src/adapters/tool-adapter.tspackages/mcp-server/src/adapters/ToolAdapter.ts renamed to packages/mcp-server/src/adapters/tool-adapter.ts packages/mcp-server/src/adapters/ToolAdapter.ts renamed to packages/mcp-server/src/adapters/tool-adapter.ts

@@ -3,8 +3,8 @@
  * Handles protocol, routing, and adapter coordination
  */
 
-import { AdapterRegistry, type RegistryConfig } from '../adapters/AdapterRegistry';
-import type { ToolAdapter } from '../adapters/ToolAdapter';
+import { AdapterRegistry, type RegistryConfig } from '../adapters/adapter-registry';
+import type { ToolAdapter } from '../adapters/tool-adapter';
 import type { AdapterContext, Config, ToolExecutionContext } from '../adapters/types';
 import { ConsoleLogger } from '../utils/logger';
 import { JSONRPCHandler } from './protocol/jsonrpc';
@@ -18,8 +18,8 @@ import type {
   ServerInfo,
   ToolCall,
 } from './protocol/types';
-import { StdioTransport } from './transport/StdioTransport';
-import type { Transport, TransportMessage } from './transport/Transport';
+import { StdioTransport } from './transport/stdio-transport';
+import type { Transport, TransportMessage } from './transport/transport';
 
 export interface MCPServerConfig {
   serverInfo: ServerInfo;
@@ -35,7 +35,6 @@ export class MCPServer {
   private logger = new ConsoleLogger('[MCP Server]');
   private config: Config;
   private serverInfo: ServerInfo;
-  private initialized = false;
 
   constructor(config: MCPServerConfig) {
     this.config = config.config;
@@ -163,8 +162,6 @@ export class MCPServer {
    * Handle initialize request
    */
   private handleInitialize(): InitializeResult {
-    this.initialized = true;
-
     const capabilities: ServerCapabilities = {
       tools: { supported: true },
       resources: { supported: false }, // Not yet implemented

packages/mcp-server/src/index.ts

@@ -6,7 +6,7 @@
 import * as readline from 'readline';
 import { JSONRPCHandler } from '../protocol/jsonrpc';
 import type { JSONRPCNotification, JSONRPCResponse } from '../protocol/types';
-import { Transport, type TransportMessage } from './Transport';
+import { Transport, type TransportMessage } from './transport';
 
 export class StdioTransport extends Transport {
   private messageHandler?: (message: TransportMessage) => void | Promise<void>;

…kages/mcp-server/src/server/MCPServer.ts …ages/mcp-server/src/server/mcp-server.tspackages/mcp-server/src/server/MCPServer.ts renamed to packages/mcp-server/src/server/mcp-server.ts packages/mcp-server/src/server/MCPServer.ts renamed to packages/mcp-server/src/server/mcp-server.ts

@@ -0,0 +1,86 @@
+/**
+ * Utilities for handling MCP protocol messages
+ */
+
+import type { AdapterRegistry } from '../../adapters/adapter-registry';
+import type {
+  InitializeResult,
+  ServerCapabilities,
+  ServerInfo,
+  ToolDefinition,
+} from '../protocol/types';
+
+/**
+ * Create initialization result
+ */
+export function createInitializeResult(
+  serverInfo: ServerInfo,
+  capabilities: ServerCapabilities
+): InitializeResult {
+  return {
+    protocolVersion: '1.0.0',
+    serverInfo,
+    capabilities,
+  };
+}
+
+/**
+ * Create tools list result
+ */
+export function createToolsListResult(registry: AdapterRegistry): { tools: ToolDefinition[] } {
+  return {
+    tools: registry.getToolDefinitions(),
+  };
+}
+
+/**
+ * Extract tool call parameters from request
+ */
+export function extractToolCallParams(
+  params: unknown
+): { name: string; arguments: Record<string, unknown> } | null {
+  if (!params || typeof params !== 'object') {
+    return null;
+  }
+
+  const p = params as Record<string, unknown>;
+
+  if (typeof p.name !== 'string') {
+    return null;
+  }
+
+  if (typeof p.arguments !== 'object' || p.arguments === null) {
+    return null;
+  }
+
+  return {
+    name: p.name,
+    arguments: p.arguments as Record<string, unknown>,
+  };
+}
+
+/**
+ * Validate JSON-RPC request structure
+ */
+export function validateRequest(request: unknown): boolean {
+  if (!request || typeof request !== 'object') {
+    return false;
+  }
+
+  const req = request as Record<string, unknown>;
+
+  // Must have jsonrpc and method
+  if (req.jsonrpc !== '2.0' || typeof req.method !== 'string') {
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * Check if method is supported
+ */
+export function isSupportedMethod(method: string): boolean {
+  const supportedMethods = ['initialize', 'tools/list', 'tools/call'];
+  return supportedMethods.includes(method);
+}