Backfill missing lab metadata (18 files)

[LuizMacedo]

This PR backfills missing lab metadata in markdown files.

Rules used:

• Add-only (does not overwrite existing metadata keys)
• Keys: lab.title, lab.description, lab.duration, lab.level, lab.islab
• Optional casing normalization to lowercase when enabled

Files changed: 18

• Instructions/Exercises/01-analyze-text.md (islab,primarytopics)
• Instructions/Exercises/02-language-agent.md (islab,primarytopics)
• Instructions/Exercises/03-gen-ai-speech.md (islab)
• Instructions/Exercises/04-azure-speech.md (islab,primarytopics)
• Instructions/Exercises/05-azure-speech-mcp.md (islab,primarytopics)
• Instructions/Exercises/06-voice-live-agent.md (islab,primarytopics)
• Instructions/Exercises/07-translation.md (islab,primarytopics)
• Instructions/Labs/01-analyze-text.md (duration,level,islab,primarytopics)
• Instructions/Labs/02-qna.md (duration,level,islab,primarytopics)
• Instructions/Labs/03-language-understanding.md (duration,level,islab,primarytopics)
• Instructions/Labs/04-text-classification.md (duration,level,islab,primarytopics)
• Instructions/Labs/05-extract-custom-entities.md (duration,level,islab,primarytopics)
• Instructions/Labs/06-translate-text.md (duration,level,islab,primarytopics)
• Instructions/Labs/07-speech.md (duration,level,islab)
• Instructions/Labs/08-translate-speech.md (duration,level,islab)
• Instructions/Labs/09-audio-chat.md (duration,level,islab,primarytopics)
• Instructions/Labs/10-voice-live-api.md (duration,level,islab,primarytopics)
• Instructions/Labs/11-voice-live-agent-web.md (duration,level,islab,primarytopics)

[GraemeMalcolm]

Only the labs in the Exercises folder should have islab=true. The ones in the Labs folder are deprecated.

[LuizMacedo]

@GraemeMalcolm I’m not sure if we should close this or fix it. The spreadsheet says “Done,” but the exercises are labs. Who is the content owner we can work with to fix this (remove from labs, keep exercises)? Thanks!

[GraemeMalcolm]

Exercises are THE SAME THING as labs.

The markdown files in the "Labs" folder are deprecated. The ones in the "Exercises" folder are the replacements.

[LuizMacedo]

@GraemeMalcolm I know. Got confused with your comment "Only the labs in the Exercises folder should have islab=true." Thanks for checking!

[GraemeMalcolm]

That's correct. We don't want the deprecated labs in the Labs folder to be included in the catalog. They're only being kept to support AI-102 until it retires next month. The ones in the Exercises folder are the current labs.