chore: automate component page generation from CEM and samples.json

[nnaydenow]

Introduce a @ui5subcomponent JSDoc tag and wire it through the CEM pipeline
to drive automatic MDX generation for the documentation website.

CEM / tooling changes:

• Add @ui5subcomponent JSDoc tag support to the CEM plugin and internal schema, emitting _ui5subcomponents string[] on parent component declarations
• Annotate all parent components across main, fiori, compat and ai packages with @ui5subcomponent tags for their child elements
• Normalise all @since tags across the codebase by stripping -rc suffixes

Website generation changes:

• Add samples.json to each package folder (main, fiori, compat, ai) describing available samples per component (name, title, description, isBasic flag)
• Exclude samples.json from gitignore while keeping generated content ignored
• Extract clean step into build-scripts/clean-components.mjs, preserving samples.json across regeneration cycles
• Rewrite api-reference-generation/components.mjs to generate MDX directly from the CEM: components with _ui5subcomponents get a folder with category.json and subcomponent files; flat components get a single MDX file
• Automatically apply newComponentBadge sidebar_class_name to any component whose _ui5since version falls within the last 6 minor releases relative to the current package.json version; deprecated components are excluded
• Fix sample import path depth for subfolder vs flat files
• Rename mismatched sample .md wrapper files to match their folder names

TODO

• Fix component pages slug genaration