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>

.env.example

@@ -36,6 +36,10 @@ MCP_SERVER_HOST=localhost
 # Server mode: stdio (local) or http (remote)
 MCP_MODE=stdio
 
+# Use fixed HTTP implementation (recommended for stability)
+# Set to true to bypass StreamableHTTPServerTransport issues
+USE_FIXED_HTTP=true
+
 # HTTP Server Configuration (only used when MCP_MODE=http)
 PORT=3000
 HOST=0.0.0.0