Release v0.21.0: LSP Protocol Compliance Fixes

🛠️ LSP PROTOCOL COMPLIANCE FIXES

- Critical LSP protocol violations preventing VS Code extension compatibility
- Debug messages mixing with LSP protocol messages on stdout
- Malformed Content-Length headers corrupting protocol communication
- UVM Class Database initialization logging breaking protocol startup

- Complete process output stream separation (stdout for LSP, stderr for debug)
- 13 LSP provider files updated with proper error handling
- Graceful error recovery without protocol corruption
- Professional IDE experience foundation established

- VS Code extension compatibility restored
- 100% LSP 3.17 specification compliance achieved
- Foundation for reliable SystemVerilog extension development
- Professional IDE experience enabled for SystemVerilog developers

Technical: Proper Content-Length header format maintained, robust error handling
without breaking LSP communication, backward compatibility preserved.