docs: update README and documentation to match current state (v2.5.1)

- Update n8n version from v1.97.1 to v1.99.1 in README
- Fix 7 broken documentation links to point to existing files
- Standardize Docker image size to ~280MB across all docs (was inconsistent: 150MB/200MB/283MB)
- Add missing npm scripts for test commands (test:essentials, test:enhanced-validation, etc.)
- Update CHANGELOG.md with missing versions 2.4.0 through 2.5.1
- Update README_CLAUDE_SETUP.md to list all 21+ MCP tools (was only showing 6)
- Document 5 additional npm scripts in CLAUDE.md
- Update AI-capable nodes count to 263 (was 35 in old docs)

All documentation now accurately reflects the current codebase state.

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

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

docs/DOCKER_README.md

@@ -39,7 +39,7 @@ curl http://localhost:3000/health
 Pre-built images are available on GitHub Container Registry:
 
 ```bash
-# Pull the latest image (~150MB optimized)
+# Pull the latest image (~280MB optimized)
 docker pull ghcr.io/czlonkowski/n8n-mcp:latest
 
 # Run with HTTP mode
@@ -434,7 +434,7 @@ secrets:
 ### Image Details
 
 - Base: `node:20-alpine`
-- Size: ~283MB compressed
+- Size: ~280MB compressed
 - Features: Pre-built database with all node information
 - Database: Complete SQLite with 525+ nodes
 - Architectures: `linux/amd64`, `linux/arm64`