[koculu]

Change

Plugins can now customize code rendering and backend creation through PureStackMarkdown.

• Add resolveHighlighter(lang) to select a renderer in plugin order, falling back to the default highlighter when all resolvers return null. Both resolution and rendering support sync and async execution.
• Add createShiki(options) and createHighlightJs() factories for custom backend initialization. Reject competing factories for the selected backend.
• Support custom block HTML, fragments, and empty output in Markdown and Regor MDX, including fences inside components.
• Rename the shared highlighting module to codeHighlighting.ts, document the API, and add regression coverage.
• Bump workspace versions and generator metadata to 1.1.11.

Validation

• Repository TypeScript check: yarn tsc --noEmit passed, including tests.
• Focused plugin, Markdown, MDX, and highlighting suites: 97 tests passed.
• Biome and diff checks passed.