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/README.md

@@ -6,8 +6,10 @@ Neovim support for the Lux programming language.
 
 - Syntax highlighting (vim regex and tree-sitter)
 - LSP integration (diagnostics, hover, completions, go-to-definition)
+- Tree-sitter text objects for code navigation
+- Code folding
+- REPL integration with send-to-REPL
 - Commands for running, formatting, and testing
-- REPL integration
 
 ## Installation
 
@@ -23,10 +25,19 @@ Neovim support for the Lux programming language.
       lsp = {
         enabled = true,
         autostart = true,
+        inlay_hints = false, -- requires neovim 0.10+
       },
       format = {
         on_save = false,
       },
+      repl = {
+        position = "bottom", -- "bottom", "right", or "float"
+        size = 30,           -- percentage of screen
+      },
+      diagnostics = {
+        virtual_text = true,
+        update_in_insert = false,
+      },
     })
   end,
   ft = "lux",
@@ -58,6 +69,7 @@ ln -s /path/to/lux/editors/nvim/ftdetect ~/.config/nvim/ftdetect
 ln -s /path/to/lux/editors/nvim/ftplugin ~/.config/nvim/ftplugin
 ln -s /path/to/lux/editors/nvim/syntax ~/.config/nvim/syntax
 ln -s /path/to/lux/editors/nvim/lua/lux ~/.config/nvim/lua/lux
+ln -s /path/to/lux/editors/nvim/after ~/.config/nvim/after
 ```
 
 ## Tree-sitter Support
@@ -69,6 +81,32 @@ For tree-sitter based highlighting, install the grammar:
 require("nvim-treesitter.configs").setup({
   ensure_installed = { "lux" },
   highlight = { enable = true },
+  indent = { enable = true },
+  -- Enable text objects
+  textobjects = {
+    select = {
+      enable = true,
+      keymaps = {
+        ["af"] = "@function.outer",
+        ["if"] = "@function.inner",
+        ["ac"] = "@class.outer",
+        ["ic"] = "@class.inner",
+        ["ab"] = "@block.outer",
+        ["ib"] = "@block.inner",
+      },
+    },
+    move = {
+      enable = true,
+      goto_next_start = {
+        ["]f"] = "@function.outer",
+        ["]c"] = "@class.outer",
+      },
+      goto_previous_start = {
+        ["[f"] = "@function.outer",
+        ["[c"] = "@class.outer",
+      },
+    },
+  },
 })
 
 -- Register the parser
@@ -89,7 +127,11 @@ parser_config.lux = {
 | `:LuxRun` | Run the current file |
 | `:LuxFormat` | Format the current file |
 | `:LuxTest` | Run tests |
+| `:LuxCheck` | Type check the current file |
 | `:LuxRepl` | Start the REPL in a terminal |
+| `:LuxReplToggle` | Toggle the REPL window |
+| `:LuxSendLine` | Send current line to REPL |
+| `:'<,'>LuxSend` | Send selection to REPL |
 
 ## Key Mappings
 
@@ -100,18 +142,56 @@ Default mappings in Lux files (using `<localleader>`):
 | `<localleader>r` | Run current file |
 | `<localleader>f` | Format current file |
 | `<localleader>t` | Run tests |
+| `<localleader>c` | Type check file |
+| `<localleader>R` | Toggle REPL |
+| `<localleader>l` | Send line to REPL |
+| `<localleader>s` (visual) | Send selection to REPL |
 
 LSP mappings (when LSP is active):
 
 | Mapping | Action |
 |---------|--------|
 | `gd` | Go to definition |
+| `gD` | Go to declaration |
 | `K` | Hover information |
 | `gr` | Find references |
+| `gi` | Go to implementation |
 | `<leader>rn` | Rename symbol |
 | `<leader>ca` | Code actions |
+| `<leader>e` | Show diagnostics float |
+| `<leader>q` | Diagnostics to location list |
 | `[d` / `]d` | Previous/next diagnostic |
 
+## REPL Integration
+
+The REPL can be positioned at the bottom, right, or as a floating window:
+
+```lua
+require("lux").setup({
+  repl = {
+    position = "float", -- floating window
+    size = 30,
+  },
+})
+```
+
+Send code to the running REPL:
+- `<localleader>l` - Send current line
+- Select code visually, then `<localleader>s` - Send selection
+
+## Text Objects
+
+With `nvim-treesitter-textobjects`, you can use:
+
+| Object | Description |
+|--------|-------------|
+| `af`/`if` | Function outer/inner |
+| `ac`/`ic` | Type/class outer/inner |
+| `ab`/`ib` | Block outer/inner |
+| `aa`/`ia` | Parameter outer/inner |
+
+Example: `dif` deletes the body of a function, `vaf` selects the entire function.
+
 ## Configuration
 
 ```lua
@@ -124,11 +204,27 @@ require("lux").setup({
     enabled = true,
     -- Auto-start LSP when opening .lux files
     autostart = true,
+    -- Show inlay hints (requires neovim 0.10+)
+    inlay_hints = false,
   },
 
   format = {
     -- Format on save
     on_save = false,
   },
+
+  repl = {
+    -- Position: "bottom", "right", or "float"
+    position = "bottom",
+    -- Size as percentage of screen
+    size = 30,
+  },
+
+  diagnostics = {
+    -- Show virtual text for diagnostics
+    virtual_text = true,
+    -- Update diagnostics in insert mode
+    update_in_insert = false,
+  },
 })
 ```