feat(lsp): add context-aware completion ranking and document highlights

Adds context-aware completion ranking and document highlights for Tcl.
Adds completion_context to distinguish variables and commands.
Wires per-file completion snapshots and ranking into the flow.
Adds document_highlight provider support and tests for highlights.

- Context-aware ranking of completion items using per-file snapshots
- Document highlight provider wired into initialization and tests
- Tests for completion context, ranking, and document highlights

README.md

@@ -11,6 +11,8 @@ A comprehensive VS Code extension providing language support and remote debuggin
 - **Auto-completion** - Context-aware code completion for faster development
 - **Signature Help** - Shows parameters and documentation for custom and NX procedures
 - **Call Hierarchy** - Traces incoming and outgoing calls between custom TCL procedures and MOM event handlers
+- **Document Highlights** - Highlights all reads, writes, and calls of the symbol under the cursor
+- **Context-aware Completion** - Prioritizes local symbols and suggests variables or commands based on cursor context
 - **NX Tcl Remote Debugger** - Breakpoints, stepping, call stack, scopes, variables, watches, evaluation, logpoints, hit conditions, and Tcl error stops directly in a running NX Post process
 
 ## Supported File Types
@@ -98,6 +100,8 @@ Simply open any supported file type and enjoy:
 - Hover information
 - Signature help while entering procedure arguments
 - Incoming and outgoing call hierarchy for custom procedures and MOM event handlers
+- Document-wide highlights for procedure and variable occurrences
+- Context-aware completion with local symbols ranked before workspace and built-in symbols
 - Remote NX Tcl debugging with breakpoints and full stepping
 
 ## Contributing