feat: Add NotebookLM skills (50-53) for Claude Code and Desktop

Add 4 specialized NotebookLM skills based on notebooklm-py library:

- 50-notebooklm-agent: Q&A agent for notebook queries with citations
- 51-notebooklm-automation: Full notebook/source/artifact management
- 52-notebooklm-studio: Content generation (podcasts, videos, quizzes)
- 53-notebooklm-research: Web/Drive research and source discovery

Each skill includes:
- README.md: Overview and quick start
- code/CLAUDE.md: Claude Code version (concise)
- desktop/SKILL.md: Claude Desktop version (with YAML frontmatter)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

custom-skills/52-notebooklm-studio/desktop/SKILL.md

@@ -0,0 +1,138 @@
+---
+name: notebooklm-studio
+description: |
+  Content generation for NotebookLM Studio artifacts - podcasts, videos, quizzes, flashcards, and more.
+  Triggers: create podcast, generate video, make quiz, 팟캐스트 만들기, 퀴즈 생성, NotebookLM 스튜디오.
+---
+
+# NotebookLM Studio
+
+Generate all NotebookLM Studio content types: audio, video, quizzes, flashcards, slide decks, infographics, mind maps, and data tables.
+
+## Prerequisites
+
+```bash
+pip install notebooklm-py
+playwright install chromium
+notebooklm login
+```
+
+## When This Skill Activates
+
+- "Create a podcast about my sources"
+- "Generate a video explainer"
+- "Make flashcards for studying"
+- "Turn this into a quiz"
+- Korean: "팟캐스트 만들어줘", "비디오 생성", "퀴즈 만들기"
+
+## Content Types
+
+| Type | Command | Options | Output |
+|------|---------|---------|--------|
+| **Audio** | `generate audio` | `--format`, `--length`, `--language` | MP3 |
+| **Video** | `generate video` | `--style`, `--format` | MP4 |
+| **Quiz** | `generate quiz` | `--difficulty`, `--quantity` | JSON/MD/HTML |
+| **Flashcards** | `generate flashcards` | `--difficulty`, `--quantity` | JSON/MD/HTML |
+| **Slide Deck** | `generate slide-deck` | `--format`, `--length` | PDF |
+| **Infographic** | `generate infographic` | `--orientation`, `--detail` | PNG |
+| **Mind Map** | `generate mind-map` | (instant) | JSON |
+| **Data Table** | `generate data-table` | description required | CSV |
+| **Report** | `generate report` | `--format` | Markdown |
+
+## Quick Reference
+
+### Generate Content
+
+```bash
+# Audio (podcast)
+notebooklm generate audio "Focus on key findings"
+notebooklm generate audio --format debate --length longer
+
+# Video
+notebooklm generate video --style whiteboard
+notebooklm generate video --style anime "Make it fun"
+
+# Quiz & Flashcards
+notebooklm generate quiz --difficulty hard --quantity more
+notebooklm generate flashcards --quantity standard
+
+# Visual content
+notebooklm generate slide-deck --format detailed
+notebooklm generate infographic --orientation portrait
+notebooklm generate mind-map
+
+# Data extraction
+notebooklm generate data-table "Compare all methods mentioned"
+notebooklm generate report --format study_guide
+```
+
+### Download Artifacts
+
+```bash
+# Check status first
+notebooklm artifact list
+
+# Download when ready
+notebooklm download audio ./podcast.mp3
+notebooklm download video ./overview.mp4
+notebooklm download quiz --format markdown ./quiz.md
+notebooklm download flashcards --format json ./cards.json
+notebooklm download slide-deck ./slides.pdf
+notebooklm download infographic ./infographic.png
+notebooklm download mind-map ./mindmap.json
+notebooklm download data-table ./data.csv
+```
+
+## Video Styles
+
+| Style | Description |
+|-------|-------------|
+| `classic` | Standard presentation |
+| `whiteboard` | Hand-drawn whiteboard |
+| `kawaii` | Cute animated style |
+| `anime` | Japanese animation |
+| `pixel` | 8-bit pixel art |
+| `watercolor` | Painted aesthetic |
+| `neon` | Glowing neon effects |
+| `paper` | Paper cutout animation |
+| `sketch` | Pencil sketch style |
+
+## Audio Formats
+
+| Format | Description |
+|--------|-------------|
+| `deep-dive` | Comprehensive exploration |
+| `brief` | Quick summary |
+| `critique` | Critical analysis |
+| `debate` | Two-sided discussion |
+
+## Processing Times
+
+| Type | Typical Time | Timeout |
+|------|--------------|---------|
+| Mind map | Instant | - |
+| Quiz/Flashcards | 5-15 min | 900s |
+| Audio | 10-20 min | 1200s |
+| Video | 15-45 min | 2700s |
+
+## Autonomy Rules
+
+**Auto-run:** `artifact list`, `artifact wait` (in subagent)
+**Ask first:** `generate *`, `download *`
+
+## Language Settings
+
+```bash
+notebooklm language list        # Show 80+ languages
+notebooklm language set ja      # Japanese
+notebooklm language set ko      # Korean
+notebooklm language set zh_Hans # Simplified Chinese
+```
+
+## Error Handling
+
+| Error | Solution |
+|-------|----------|
+| Rate limited | Wait 5-10 min, retry |
+| Generation failed | Check `artifact list`, retry later |
+| Download fails | Ensure artifact status is `completed` |