feat: add interactive attribute block toggle with keybindings and commands

Add ability to expand/collapse SCL variable attribute blocks like {EXTERNALACCESSIBLE := 'false'} to {...}

Features:
- Per-variable collapse rules via collapseVariableRules option
- Interactive toggle with <Leader>xa keybinding
- Commands: SCLToggleAttrBlock, SCLExpandAllAttrBlocks, SCLCollapseAllAttrBlocks
- Keybindings: <Leader>xa (toggle), <Leader>xae (expand all), <Leader>xac (collapse all)
- Supports both formatter-collapsed and manually collapsed blocks

Also update AGENTS.md with new documentation and troubleshooting guide

lua/scl/init.lua

@@ -88,6 +88,9 @@ function M.setup(opts)
 
   -- Multiline parameters feature
   M.setup_multiline_params()
+
+  -- Attribute block toggle feature
+  M.setup_attr_toggle()
 end
 
 function M.setup_multiline_params()
@@ -171,6 +174,76 @@ function M.create_commands()
   vim.api.nvim_create_user_command("SCLShowVariables", function() M.show_variables() end, {})
   vim.api.nvim_create_user_command("SCLShowWorkspaceTypes", function() M.show_workspace_types() end, {})
   vim.api.nvim_create_user_command("SCLRescanWorkspaceTypes", function() M.rescan_workspace_types() end, {})
+  
+  -- Attribute toggle commands
+  vim.api.nvim_create_user_command("SCLToggleAttrBlock", function()
+    local ok, at = pcall(require, "scl.attr_toggle")
+    if ok then
+      at.toggle_attr_block()
+    else
+      vim.notify("SCL: Failed to load attr_toggle module", vim.log.levels.ERROR)
+    end
+  end, {})
+  vim.api.nvim_create_user_command("SCLExpandAllAttrBlocks", function()
+    local ok, at = pcall(require, "scl.attr_toggle")
+    if ok then
+      at.expand_all_attr_blocks()
+    else
+      vim.notify("SCL: Failed to load attr_toggle module", vim.log.levels.ERROR)
+    end
+  end, {})
+  vim.api.nvim_create_user_command("SCLCollapseAllAttrBlocks", function()
+    local ok, at = pcall(require, "scl.attr_toggle")
+    if ok then
+      at.collapse_all_attr_blocks()
+    else
+      vim.notify("SCL: Failed to load attr_toggle module", vim.log.levels.ERROR)
+    end
+  end, {})
+end
+
+function M.setup_attr_toggle()
+  local at = require("scl.attr_toggle")
+  at.setup()
+
+  local function setup_buffer_keymaps(bufnr)
+    local opts = { buffer = bufnr, silent = true }
+    local ft = vim.bo[bufnr].filetype
+    
+    if ft ~= "scl" and ft ~= "udt" then
+      return
+    end
+
+    -- Toggle individual attribute block under cursor
+    vim.keymap.set({ "n", "i" }, "<Leader>xa", function()
+      at.toggle_attr_block()
+    end, vim.tbl_extend("force", opts, { desc = "SCL: Toggle attribute block" }))
+
+    -- Expand all collapsed blocks
+    vim.keymap.set("n", "<Leader>xae", function()
+      at.expand_all_attr_blocks()
+    end, vim.tbl_extend("force", opts, { desc = "SCL: Expand all attribute blocks" }))
+
+    -- Collapse all attribute blocks
+    vim.keymap.set("n", "<Leader>xac", function()
+      at.collapse_all_attr_blocks()
+    end, vim.tbl_extend("force", opts, { desc = "SCL: Collapse all attribute blocks" }))
+  end
+
+  -- Set up keybindings for SCL files only
+  vim.api.nvim_create_autocmd("FileType", {
+    pattern = { "scl", "udt" },
+    callback = function(args)
+      setup_buffer_keymaps(args.buf)
+    end,
+  })
+  
+  -- Also check if there are already SCL buffers open
+  for _, bufnr in ipairs(vim.api.nvim_list_bufs()) do
+    if vim.api.nvim_buf_is_loaded(bufnr) then
+      setup_buffer_keymaps(bufnr)
+    end
+  end
 end
 
 return M