docs: update README with attribute block toggle feature

Add documentation for new attribute block toggle feature including:
- New commands: SCLToggleAttrBlock, SCLExpandAllAttrBlocks, SCLCollapseAllAttrBlocks
- New keybindings: <Leader>xa, <Leader>xae, <Leader>xac
- Feature description and usage example

README.md

@@ -48,6 +48,7 @@ A comprehensive Neovim/LazyVim plugin providing **Language Server Protocol (LSP)
 | **Workspace UDT Scanner** | Scans project for user-defined types (.udt files) |
 | **Workspace Global DB Scanner** | Scans project for global data blocks (.db files) |
 | **blink.cmp Integration** | Smart completion source for blink.cmp |
+| **Attribute Block Toggle** | Interactive expand/collapse of `{...}` blocks with `<Leader>xa` |
 
 ## Installation
 
@@ -116,6 +117,9 @@ require("scl_lsp").setup({
 | `:SCLMultilineParams` | Fill multiline parameters for FB/Function call |
 | `:LspSCLFormat` | Format current SCL file |
 | `:SCLGeneratePlcJson` | Generate plc.data.json from data_types/ |
+| `:SCLToggleAttrBlock` | Toggle attribute block under cursor |
+| `:SCLExpandAllAttrBlocks` | Expand all `{...}` blocks in buffer |
+| `:SCLCollapseAllAttrBlocks` | Collapse all matching attribute blocks |
 
 ## Keybindings
 
@@ -127,9 +131,32 @@ require("scl_lsp").setup({
 | `<leader>w` | Workspace Symbols |
 | `<Space>mp` | Fill multiline FB/Function parameters (insert mode) |
 | `<Tab>` | Jump to next parameter (insert mode) |
+| `<Leader>xa` | Toggle attribute block under cursor |
+| `<Leader>xae` | Expand all attribute blocks |
+| `<Leader>xac` | Collapse all attribute blocks |
 | `<leader>fw` | Workspace Symbols (Telescope) |
 | `<leader>ca` | Code Actions |
 
+## Attribute Block Toggle
+
+Interactive expand/collapse of SCL variable attribute blocks:
+
+```scl
+-- Before: Verbose attributes
+statCounter{EXTERNALACCESSIBLE := 'false'; EXTERNALVISIBLE := 'false'} : Int;
+
+-- After: Collapsed
+statCounter{...} : Int;
+```
+
+**Usage:**
+- Place cursor inside any `{...}` block
+- Press `<Leader>xa` to toggle expand/collapse
+- Use `<Leader>xae` to expand all blocks in buffer
+- Use `<Leader>xac` to collapse all blocks
+
+The formatter also supports automatic collapsing via `collapseAttributes` option.
+
 ## External UDT Support
 
 ### Option 1: Create `.plc.json`