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/nvim/after/queries/lux/highlights.scm

@@ -0,0 +1,141 @@
+; Syntax highlighting queries for Lux
+
+; Comments
+(line_comment) @comment
+(doc_comment) @comment.documentation
+
+; Keywords
+[
+  "fn"
+  "let"
+  "type"
+  "effect"
+  "handler"
+  "trait"
+  "impl"
+  "for"
+  "import"
+  "export"
+  "match"
+  "if"
+  "then"
+  "else"
+  "with"
+  "run"
+  "resume"
+  "is"
+] @keyword
+
+; Operators
+[
+  "+"
+  "-"
+  "*"
+  "/"
+  "%"
+  "=="
+  "!="
+  "<"
+  ">"
+  "<="
+  ">="
+  "&&"
+  "||"
+  "!"
+  "="
+  "=>"
+  "|>"
+  ":"
+  "|"
+  "."
+  ","
+] @operator
+
+; Punctuation
+[
+  "("
+  ")"
+  "{"
+  "}"
+  "["
+  "]"
+  "<"
+  ">"
+] @punctuation.bracket
+
+; Literals
+(integer) @number
+(float) @number.float
+(string) @string
+(char) @character
+(boolean) @boolean
+(unit) @constant.builtin
+
+; String interpolation
+(interpolation
+  "{" @punctuation.special
+  "}" @punctuation.special)
+
+(escape_sequence) @string.escape
+
+; Types
+(type_expression (identifier) @type)
+(generic_type (identifier) @type)
+(type_declaration name: (identifier) @type.definition)
+(type_parameters (identifier) @type.parameter)
+
+; Built-in types
+((identifier) @type.builtin
+  (#match? @type.builtin "^(Int|Float|Bool|String|Char|Unit|Option|Result|List)$"))
+
+; Functions
+(function_declaration name: (identifier) @function.definition)
+(call_expression function: (identifier) @function.call)
+(call_expression function: (member_expression member: (identifier) @function.method))
+
+; Effect operations
+(effect_declaration name: (identifier) @type.definition)
+(effect_operation name: (identifier) @function.definition)
+(handler_declaration name: (identifier) @function.definition)
+(handler_declaration effect: (identifier) @type)
+(handler_operation name: (identifier) @function.definition)
+
+; Traits
+(trait_declaration name: (identifier) @type.definition)
+(trait_method name: (identifier) @function.definition)
+(impl_declaration trait: (identifier) @type)
+
+; Parameters
+(parameter name: (identifier) @variable.parameter)
+
+; Variables
+(let_declaration name: (identifier) @variable.definition)
+(identifier) @variable
+
+; Patterns
+(pattern (identifier) @variable)
+(constructor_pattern name: (identifier) @constructor)
+(field_pattern name: (identifier) @property)
+
+; Record fields
+(field_assignment name: (identifier) @property)
+(record_field name: (identifier) @property)
+
+; Member access
+(member_expression member: (identifier) @property)
+
+; Modules (capitalized identifiers used as module access)
+(member_expression
+  object: (identifier) @module
+  (#match? @module "^[A-Z]"))
+
+; Variants/Constructors (capitalized identifiers)
+((identifier) @constructor
+  (#match? @constructor "^[A-Z][a-zA-Z0-9]*$"))
+
+; Special identifiers
+((identifier) @constant.builtin
+  (#match? @constant.builtin "^(None|Some|Ok|Err|true|false)$"))
+
+; Property annotations
+(property_clause (identifier) @attribute)