Add title format transformations for template variables

[linyows]

Summary

• Add {{@title{format}}} template syntax to transform titles into filename-friendly formats
• Supported formats: snake, kebab, lower, camel, pascal
• Handles spaces, mixed separators, and camelCase boundaries

Examples

Syntax	Input	Output
{{@title{snake}}}	API Design Review	api_design_review
{{@title{kebab}}}	API Design Review	api-design-review
{{@title{lower}}}	API Design Review	api design review
{{@title{camel}}}	API Design Review	apiDesignReview
{{@title{pascal}}}	API Design Review	ApiDesignReview

Usage in config

{
  "filename_format": "{{@id{4}}}-{{@title{kebab}}}.md"
}

draft adr "Authentication System" → 0001-authentication-system.md

Both {{@title}} and {{@title{format}}} can be used together in the same template.

Test plan

• Unit tests for each transformation function (snake, kebab, lower, camel, pascal)
• Tests for edge cases: camelCase input, mixed separators, consecutive spaces
• Integration tests for replaceTitleWithFormat within template strings
• Integration tests for replaceVariables with combined {{@title}} and {{@title{format}}}
• All existing tests still pass

🤖 Generated with Claude Code