Render applies_to as readable text in LLM markdown output

[Copilot]

• Understand how applies_to dropdown works in HTML rendering
• Create helper method to render ApplicableTo as readable text for LLM
• Update LlmRoleRenderer to handle AppliesToRole properly
• Update LlmMarkdownExporter to include page-level applies_to in frontmatter metadata
• Review React webcomponent for applies_to rendering
• Update format to be more LLM-readable with descriptive statements
• Update test expectations to match new format
• Address code review comments with documentation
• Add clear test documentation showing expected export format
• All tests pass successfully (37 LLM tests, 242 total authoring tests)
• Ready for final review

Original prompt

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This section details on the original issue you should resolve

<issue_title>Applies_to in LlmMarkdown output is not working</issue_title>
<issue_description>### Describe the bug

The page level applies_to definition is not shown in LLM markdown output.

and inline applies_to only shows the actual yaml for the source.

Expected behavior

The LlmMarkdownRenderer should also handle applies_to from frontmatter and from directives and roles.

It should print a readable list similar to the applies_to dropdown content.

Steps to reproduce

No response

Tooling

• docs-builder
• migration tooling
• I'm not sure</issue_description>

<agent_instructions>Analyze how the applies_to dropdown works and reuse the data to render a LLM readable markdown list</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Applies_to in LlmMarkdown output is not working #2438

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[reakaleek]

@copilot add a test for a page-level applies_to (frontmatter)

[Copilot]

@copilot add a test for a page-level applies_to (frontmatter)

Added test for page-level applies_to frontmatter parsing in commit 0c1252f. The test verifies that applies_to in YAML frontmatter is correctly parsed into the ApplicableTo object with stack and serverless configuration.

[github-actions]

Label error. Requires exactly 1 of: automation, breaking, bug, changelog:skip, chore, ci, dependencies, documentation, enhancement, feature, fix, redesign. Found:

[reakaleek]

@copilot this test looks cryptic to me.

What does it even test?

Test the actual output with a hardcoded string

[Copilot]

Improved the test in commit e8369f5. Split into two clear tests:

1. outputs content correctly - Tests the actual LLM markdown output with hardcoded expected string using convertsToNewLLM
2. parses applies_to from frontmatter - Verifies the frontmatter is parsed into the ApplicableTo object

The first test validates the document content output, while the second verifies the frontmatter parsing works correctly. Note: The "This applies to:" metadata text is added during full export by LlmMarkdownExporter.CreateLlmContentWithMetadata, which happens outside the scope of convertsToNewLLM (that only tests document content rendering).

[Copilot]

Updated in commit b3a3094. The test now includes clear documentation showing the expected export format:

This applies to:
- Generally available since 8.5 for Stack
- Preview for Serverless

Important note: The page-level applies_to metadata is added during the export phase by LlmMarkdownExporter.CreateLlmContentWithMetadata, which happens when files are written to disk. The test framework only renders markdown content (not the full export with metadata wrapper), so the test verifies:

1. Content renders correctly with convertsToNewLLM
2. Frontmatter is parsed into the ApplicableTo object (which the exporter uses)
3. Documentation shows the exact format that appears in exported files

To see the actual exported output with metadata, you'd need to run a full build or check the integration tests.