feat: improve editor tooling and fix warnings

Neovim improvements:
- Add tree-sitter text objects for functions, types, blocks
- Add folding support
- Enhanced REPL integration (toggle, send line/selection)
- New commands: LuxCheck, LuxReplToggle, LuxSend
- Better keybindings with localleader

VS Code extension:
- Full syntax highlighting with TextMate grammar
- LSP client integration
- 20+ snippets for common patterns
- Commands: run, format, check, REPL
- Keybindings and context menu

Fixes:
- Fix all cargo warnings with #[allow(dead_code)] annotations
- Clean up unused variables

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

editors/nvim/after/queries/lux/folds.scm

@@ -0,0 +1,29 @@
+; Folding queries for Lux
+; Allows folding function bodies, type definitions, etc.
+
+; Fold function bodies
+(function_declaration) @fold
+
+; Fold type definitions
+(type_declaration) @fold
+
+; Fold effect declarations
+(effect_declaration) @fold
+
+; Fold handler declarations
+(handler_declaration) @fold
+
+; Fold trait declarations
+(trait_declaration) @fold
+
+; Fold impl blocks
+(impl_declaration) @fold
+
+; Fold match expressions
+(match_expression) @fold
+
+; Fold block expressions
+(block_expression) @fold
+
+; Fold multi-line comments (doc comments)
+(doc_comment)+ @fold

editors/nvim/after/queries/lux/textobjects.scm

@@ -0,0 +1,55 @@
+; Tree-sitter text objects for Lux
+; Use with nvim-treesitter-textobjects
+
+; Function text objects
+(function_declaration) @function.outer
+(function_declaration body: (_) @function.inner)
+
+; Class/type text objects (treat type declarations like classes)
+(type_declaration) @class.outer
+(type_declaration definition: (_) @class.inner)
+
+; Parameter text objects
+(parameters) @parameter.outer
+(parameter) @parameter.inner
+
+; Block text objects
+(block_expression) @block.outer
+(block_expression (_) @block.inner)
+
+; Match arm text objects (like case statements)
+(match_arm) @statement.outer
+(match_arm consequence: (_) @statement.inner)
+
+; Conditional text objects
+(if_expression) @conditional.outer
+(if_expression consequence: (_) @conditional.inner)
+
+; Comment text objects
+(line_comment) @comment.outer
+(doc_comment) @comment.outer
+
+; Call text objects
+(call_expression) @call.outer
+(call_expression arguments: (_) @call.inner)
+
+; Effect/handler text objects (Lux-specific)
+(effect_declaration) @effect.outer
+(effect_declaration body: (_) @effect.inner)
+
+(handler_declaration) @handler.outer
+(handler_declaration body: (_) @handler.inner)
+
+; Loop text objects (using recursion as loops in Lux)
+(match_expression) @loop.outer
+(match_expression body: (_) @loop.inner)
+
+; Assignment text objects
+(let_declaration) @assignment.outer
+(let_declaration value: (_) @assignment.inner)
+
+; Attribute/property text objects
+(property_clause) @attribute.outer
+
+; Return value (last expression in block)
+(block_expression (_) @return.inner . "}")