implement variable_naming

[hashtafak]

PR: Implement Variable Naming Lint

Description

Adds variable_naming lint that validates variable, function, constant, and type names against configurable regex patterns.

Changes

• Implemented VariableNamingLint in selene-lib/src/lints/variable_naming.rs
• Default patterns:
  • variables=snake_case
  • functions=camelCase
  • constants=SCREAMING_SNAKE_CASE
  • types=PascalCase
• Configuration flags: check_locals, check_globals, check_parameters, check_functions, check_types, ignore_pattern
• AST visitor for precise error locations on functions and types
• ScopeManager integration for variable validation
• Registered in selene-lib/src/lints.rs

Tests

• All tests in selene-lib/tests/lints/variable_naming/ pass
• Unit tests cover functions, types, valid/invalid variables
• Edge cases (underscore prefix, heuristic type detection)

Configuration

# selene.toml
std = "lua51"

[lints]
variable_naming = "warn"
undefined_variable = "allow"

[config]
# Regular expressions for naming conventions
function_names = "^_?[a-z][a-zA-Z0-9]*$" # camelCase: starts with lowercase, optional underscore
variable_names = "^[a-z][a-z0-9_]*$"     # snake_case: lowercase with underscores
constant_names = "^[A-Z][A-Z0-9_]*$"     # UPPER_CASE: all caps with underscores
type_names = "^[A-Z][a-zA-Z0-9]+$"       # PascalCase: starts with uppercase

ignore_pattern = "^__?ignored"

check_locals = true
check_globals = true
check_parameters = true
check_functions = true
check_types = true

Checklist

• Builds successfully (cargo build)
• All tests pass (cargo test)
• No clippy warnings
• Backward compatible
• Documentation added