feat(server): add TCL signature help support

Adds a signature help system for TCL commands.
The LSP server now exposes signature help for custom and
built-in MOM procedures, enabling parameter hints while editing.
Tests and documentation were added to cover common usage.

- Adds signature_help module to parse and present signatures
- Integrates with LSP server to provide signature help on the client
- Adds tests for custom and built-in procedures

README.md

@@ -9,6 +9,7 @@ A comprehensive VS Code extension providing language support for NX CAM postproc
 - **Multi-language Support** - Supports NX CDL, TCL, and DEF file formats
 - **Intelligent Code Analysis** - Linting and error detection for postprocessor code
 - **Auto-completion** - Context-aware code completion for faster development
+- **Signature Help** - Shows parameters and documentation for custom and NX procedures
 
 ## Supported File Types
 
@@ -40,6 +41,7 @@ Simply open any supported file type and enjoy:
 - Code completion
 - Code formatting (Format Document command)
 - Hover information
+- Signature help while entering procedure arguments
 
 ## Contributing