refactor: Refactor DevlogManager usage and remove deprecated versions

- Updated imports in MCPDevlogAdapter to use the new DevlogManager instead of NewDevlogManager.
- Removed the test file for DevlogManager as it is no longer needed.
- Refactored web server initialization to use the new DevlogManager and adjusted the configuration accordingly.
- Updated devlog routes to use findOrCreateDevlog method instead of createDevlog.
- Cleaned up code for better readability and maintainability.

Author: Marvin Zhang

.github/copilot-instructions.md

@@ -1,5 +1,22 @@
 # Devlog Project - Copilot Instructions
 
+## Early Development Stage Guidelines
+
+**IMPORTANT**: This project is in early development. We prioritize clean, modern architecture over backwards compatibility.
+
+### Legacy Code Management
+- **Remove obsolete code**: Don't preserve legacy implementations when refactoring
+- **Modernize aggressively**: Prefer current best practices over maintaining old patterns  
+- **Clean slate approach**: It's better to rewrite than to patch outdated code
+- **Breaking changes are acceptable**: We're not bound by API compatibility during this phase
+- **Focus on the future**: Design for where we want to be, not where we've been
+
+### Development Philosophy
+- **Quality over continuity**: A well-architected solution is more valuable than preserving broken legacy code
+- **Rapid iteration**: Make bold changes to improve the codebase structure
+- **Technical debt elimination**: Actively remove code that doesn't serve the current vision
+- **Modern tooling**: Always use the latest stable versions and best practices
+
 ## Dogfooding Guidelines
 
 This project uses **itself** for development tracking. When working on devlog features, ALWAYS:

packages/core/src/__tests__/devlog-manager-v2.test.ts

@@ -19,19 +19,19 @@ import {
 
 import { StorageProvider, StorageConfig, StorageProviderFactory } from "./storage/storage-provider.js";
 
-export interface NewDevlogManagerOptions {
+export interface DevlogManagerOptions {
   workspaceRoot?: string;
   storage?: StorageConfig;
   integrations?: EnterpriseIntegration;
 }
 
-export class NewDevlogManager {
+export class DevlogManager {
   private storageProvider!: StorageProvider;
   private workspaceRoot: string;
   private integrations?: EnterpriseIntegration;
   private initialized = false;
 
-  constructor(private options: NewDevlogManagerOptions = {}) {
+  constructor(private options: DevlogManagerOptions = {}) {
     this.workspaceRoot = options.workspaceRoot || process.cwd();
     this.integrations = options.integrations;
   }