ProcessMarkdownTask #15

Implement a cacheable, incremental Gradle task that applies a configured MarkdownPipeline to a directory of .md files.

Scope

• @CacheableTask abstract class ProcessMarkdownTask : DefaultTask()
• @InputDirectory @PathSensitive(RELATIVE) abstract val sourceDir: DirectoryProperty
• @OutputDirectory abstract val outputDir: DirectoryProperty
• Pipeline configuration (transformers + options) declared via task properties
• Incremental processing via Gradle's @Incremental input API — only reprocess changed files
• Each .md file in sourceDir is processed through the pipeline and written to the corresponding path under outputDir
• Non-.md files are copied as-is

Acceptance criteria

• Task processes all .md files in the source directory
• UP-TO-DATE check works correctly — unchanged files are not reprocessed
• TemplateSubstitutor and HtmlCommentExpander are configurable on the task