refactor: major cleanup of legacy and temporary files

- Removed ~965MB of temporary directories (temp/, extracted-nodes/, etc)
- Deleted outdated database files and backups (.bak files)
- Removed legacy shell scripts (mcp-server-v20.sh, rebuild-v20.sh)
- Cleaned up orphan test files and debugging scripts
- Removed duplicate schema file (src/db/schema.sql)
- Deleted old Dockerfile.old and empty database files
- Updated documentation structure in README.md
- Added n8n_diagnostic tool to documentation
- Condensed version history in CLAUDE.md
- Created release notes for v2.7.0

Total impact: Removed 34 files, saving ~965MB+ of disk space

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

CHANGELOG.md

@@ -0,0 +1,31 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [2.7.0] - 2025-06-29
+
+### Added
+- New `n8n_diagnostic` tool to help troubleshoot management tools visibility issues
+- Version utility (`src/utils/version.ts`) to read version from package.json as single source of truth
+- Script to sync package.runtime.json version (`scripts/sync-runtime-version.js`)
+
+### Changed
+- Renamed core MCP files to remove unnecessary suffixes:
+  - `tools-update.ts` → `tools.ts`
+  - `server-update.ts` → `server.ts`
+  - `http-server-fixed.ts` → `http-server.ts`
+- Updated imports across 21+ files to use the new file names
+
+### Fixed
+- Version mismatch issue where version was hardcoded as 2.4.1 instead of reading from package.json (GitHub issue #5)
+
+### Removed
+- Legacy HTTP server implementation (`src/http-server.ts`) with known issues
+- Unused legacy API client (`src/utils/n8n-client.ts`)
+
+## [Previous versions]
+
+For changes in versions prior to 2.7.0, please refer to the git history and CLAUDE.md file which contains detailed update notes for versions 2.0.0 through 2.6.3.