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

test_example.spec.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+Describe "ShellSpec formatting test"
+# This is a top-level comment
+Context "when testing HEREDOC support"
+# Comment inside Context
+It "should preserve HEREDOC formatting"
+# Comment inside It block
+When call cat <<EOF
+    This indentation should be preserved
+      Even with deeper indentation
+    Back to original level
+EOF
+The output should include "preserved"
+End
+
+It "should handle quoted HEREDOC"
+When call cat <<'DATA'
+  # This comment inside HEREDOC should not be touched
+  Some $variable should not be expanded
+DATA
+The output should include "variable"
+End
+End
+
+Context "when testing regular formatting"
+# Another context comment
+It "should indent comments properly"
+# This comment should be indented to It level
+When call echo "test"
+# Another comment at It level
+The output should equal "test"
+End
+End
+End