feat: add devtools (tree-sitter, neovim, formatter, CLI commands)

- Add tree-sitter grammar for syntax highlighting
- Add Neovim plugin with syntax, LSP integration, and commands
- Add code formatter (lux fmt) with check mode
- Add CLI commands: fmt, check, test, watch, init
- Add project initialization with lux.toml template

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

editors/tree-sitter-lux/queries/indents.scm

@@ -0,0 +1,22 @@
+; Indent rules for Lux
+
+[
+  (block_expression)
+  (match_expression)
+  (if_expression)
+  (record_expression)
+  (list_expression)
+  (effect_declaration)
+  (handler_declaration)
+  (trait_declaration)
+  (impl_declaration)
+  (enum_definition)
+] @indent
+
+[
+  "}"
+  "]"
+  ")"
+] @outdent
+
+(match_arm "=>" @indent)