docs: update documentation for v2.3.2 and remove legacy files

Major documentation cleanup and updates:

Updates:
- Add USE_FIXED_HTTP=true to all Docker and HTTP deployment examples
- Update main README with v2.3.2 release notes and version badges
- Add HTTP server troubleshooting section for stream errors
- Update CHANGELOG with v2.3.1 and v2.3.2 entries
- Update all configuration examples (.env.example, docker-compose.yml)
- Add clear instructions for using the fixed HTTP implementation

Removed legacy documentation (11 files):
- Implementation plans that have been completed
- Architecture analysis documents
- Intermediate fix documentation
- Planning documents for features now implemented
- Duplicate SETUP.md (content merged into INSTALLATION.md)

The documentation now accurately reflects the current v2.3.2 state
with the complete HTTP server fix using USE_FIXED_HTTP=true.

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

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

docs/HTTP_DEPLOYMENT.md

@@ -15,7 +15,10 @@ The easiest way to deploy n8n-MCP is using Docker:
 #### Quick Start
 ```bash
 # 1. Create configuration
-echo "AUTH_TOKEN=$(openssl rand -base64 32)" > .env
+cat > .env << EOF
+AUTH_TOKEN=$(openssl rand -base64 32)
+USE_FIXED_HTTP=true
+EOF
 
 # 2. Start with Docker Compose
 docker compose up -d
@@ -33,6 +36,7 @@ cd n8n-mcp
 # 2. Create production .env
 cat > .env << EOF
 AUTH_TOKEN=$(openssl rand -base64 32)
+USE_FIXED_HTTP=true
 NODE_ENV=production
 LOG_LEVEL=info
 PORT=3000
@@ -87,6 +91,7 @@ Edit `.env`:
 ```env
 # HTTP mode configuration
 MCP_MODE=http
+USE_FIXED_HTTP=true  # Important: Use the fixed implementation (v2.3.2+)
 PORT=3000
 HOST=0.0.0.0