feat: add first-class Neovim support with enhanced formatting

- Add modern Lua implementation with modular architecture
- Implement HEREDOC preservation and smart comment indentation
- Create dual implementation (Neovim Lua + VimScript fallback)
- Add comprehensive health check and configuration system
- Enhance formatting engine with state machine for context awareness
- Update documentation with Lua configuration examples
- Add memory files for development workflow and conventions

lua/shellspec/init.lua

@@ -0,0 +1,90 @@
+-- Main ShellSpec module for Neovim
+local M = {}
+
+-- Lazy-load submodules
+local config = require("shellspec.config")
+local format = require("shellspec.format")
+local autocmds = require("shellspec.autocmds")
+
+-- Version info
+M._VERSION = "2.0.0"
+
+-- Setup function for Lua configuration
+function M.setup(opts)
+  opts = opts or {}
+
+  -- Setup configuration
+  config.setup(opts)
+
+  -- Setup autocommands
+  autocmds.setup()
+
+  -- Create global commands for compatibility
+  vim.api.nvim_create_user_command("ShellSpecFormat", function()
+    format.format_buffer()
+  end, { desc = "Format current ShellSpec buffer" })
+
+  vim.api.nvim_create_user_command("ShellSpecFormatRange", function(cmd_opts)
+    format.format_selection(0, cmd_opts.line1, cmd_opts.line2)
+  end, {
+    range = true,
+    desc = "Format ShellSpec selection",
+  })
+
+  -- Optional: Enable auto-format if configured
+  if config.get("auto_format") then
+    autocmds.refresh() -- Refresh to pick up auto-format settings
+  end
+end
+
+-- Format functions (for external use)
+M.format_buffer = format.format_buffer
+M.format_selection = format.format_selection
+M.format_lines = format.format_lines
+
+-- Configuration access
+M.config = config
+
+-- Health check function for :checkhealth
+function M.health()
+  local health = vim.health or require("health")
+
+  health.report_start("ShellSpec.nvim")
+
+  -- Check Neovim version
+  if vim.fn.has("nvim-0.7") == 1 then
+    health.report_ok("Neovim version >= 0.7.0")
+  else
+    health.report_warn("Neovim version < 0.7.0, some features may not work")
+  end
+
+  -- Check configuration
+  local current_config = config.config
+  if current_config then
+    health.report_ok("Configuration loaded successfully")
+    health.report_info("Auto-format: " .. tostring(current_config.auto_format))
+    health.report_info("Indent size: " .. tostring(current_config.indent_size))
+    health.report_info("Use spaces: " .. tostring(current_config.use_spaces))
+  else
+    health.report_error("Configuration not loaded")
+  end
+
+  -- Check if in ShellSpec buffer
+  local filetype = vim.bo.filetype
+  if filetype == "shellspec" then
+    health.report_ok("Current buffer is ShellSpec filetype")
+  else
+    health.report_info("Current buffer filetype: " .. (filetype or "none"))
+  end
+end
+
+-- Backward compatibility function for VimScript
+function M.format_buffer_compat()
+  format.format_buffer()
+end
+
+function M.format_selection_compat(start_line, end_line)
+  format.format_selection(0, start_line, end_line)
+end
+
+return M